Q&A - P5 Math

[simple88]

MathIzzzFun:

simple88:

Hi MathIzzzFun,

Thank you so much. Amazed how you can present it in such a way that is so much easier to comprehend than what my kid is taught in school. Sorry I have one more for you. Thanks alot.

Q)At first, Ah Jie only had oranges and Ah Siang only had apples. They gave each other half of their fruits. Ah Jie then sold 18 oranges and Ah Siang sold 8 apples. In the end, the ratio of the number of oranges to the number of apples Ah Jie had was 1:4 and the ratio of the number of oranges to the number of apples Ah Siang had was 1:3. How many oranges did Ah Jie have at first?

Hi

you can use MD, UP (unit/part) or cross-multiply method...

After selling 18 oranges,
Jie's oranges : apples --> 1u : 4u
Before selling the oranges, Jie's oranges : apples --> 1u + 18 : 4u

Siang had same number of oranges & apples
ie Siang's oranges : apples --> 1u + 18 : 4u

after selling 8 apples,
Siang's oranges : apples
--> 1u + 18 : 4u - 8
= 1 : 3

equalizing or cross-multiply:
3u + 54 = 4u -8
1u --> 62

number of oranges Jie had at first --> (62 +18)x2 = 160

cheers.

Hi,
I have problem understanding this part where you mentioned
'Siang had same number of oranges & apples
ie Siang's oranges : apples --> 1u + 18 : 4u'.

How do you know that Siang had same number of oranges & apples to form this ratio?

Thanks.

[MathIzzzFun]

simple88:

MathIzzzFun:

[quote=\"simple88\"]Hi MathIzzzFun,

Thank you so much. Amazed how you can present it in such a way that is so much easier to comprehend than what my kid is taught in school. Sorry I have one more for you. Thanks alot.

Q)At first, Ah Jie only had oranges and Ah Siang only had apples. They gave each other half of their fruits. Ah Jie then sold 18 oranges and Ah Siang sold 8 apples. In the end, the ratio of the number of oranges to the number of apples Ah Jie had was 1:4 and the ratio of the number of oranges to the number of apples Ah Siang had was 1:3. How many oranges did Ah Jie have at first?

Hi

you can use MD, UP (unit/part) or cross-multiply method...

After selling 18 oranges,
Jie's oranges : apples --> 1u : 4u
Before selling the oranges, Jie's oranges : apples --> 1u + 18 : 4u

Siang had same number of oranges & apples
ie Siang's oranges : apples --> 1u + 18 : 4u

after selling 8 apples,
Siang's oranges : apples
--> 1u + 18 : 4u - 8
= 1 : 3

equalizing or cross-multiply:
3u + 54 = 4u -8
1u --> 62

number of oranges Jie had at first --> (62 +18)x2 = 160

cheers.

Hi,
I have problem understanding this part where you mentioned
'Siang had same number of oranges & apples
ie Siang's oranges : apples --> 1u + 18 : 4u'.

How do you know that Siang had same number of oranges & apples to form this ratio?

Thanks.[/quote]\"At first, Ah Jie only had oranges and Ah Siang only had apples. They gave each other half of their fruits.\"

so, each has 1/2 the number of oranges and 1/2 the number of apples

cheers.

[999happygolucky]

Thanks to all the masters who helped to solve all the problems posted. I greatly appreciate the help, especially when my DS seemed so lost in his Maths. MILLIONS OF THANKS

[Udon]

hi..need help :?:


Thank U....

Q1 The total number of balls in Box A and Box B is 165 less than the total number of balls in Box A and Box C. The number of balls in Box C is 4 times the number of balls in Box B. The number of balls in Box D is 3 times the total number of balls in Box A and Box B. If the total number of balls in all the 4 boxes is 752.

a) How many balls are there in Box A?

b) How many balls are there in Box D?

[MathIzzzFun]

Udon:

hi..need help :?:


Thank U....

Q1 The total number of balls in Box A and Box B is 165 less than the total number of balls in Box A and Box C. The number of balls in Box C is 4 times the number of balls in Box B. The number of balls in Box D is 3 times the total number of balls in Box A and Box B. If the total number of balls in all the 4 boxes is 752.

a) How many balls are there in Box A?

b) How many balls are there in Box D?

\"The total number of balls in Box A and Box B is 165 less than the total number of balls in Box A and Box C.\" --> draw a model and one will see that there are 165 more balls in Box C than Box B

Box C - Box B = 165 --> 3 units (since Box C is 4 times Box B, difference is 3 units)
Solving, Box B --> 55, Box C --> 220
Box D --> 3A + 165

Total Box A+ Box B+ Box C+ Box D --> A+55+220+3A+165 = 752
A --> 78
D --> 399

Box A --> 78
Box B --> 55
Box C --> 220
Box D --> 399

cheers.

[ozora]

need some guide in this questions.

Rob saved 40% less than Perry.
Lucy saved 30% less than Rob.
If Lucy saved $210, how much did Perry save?

Is Rob or Perry 100%? Why?

[MathIzzzFun]

ozora:

need some guide in this questions.

Rob saved 40% less than Perry.
Lucy saved 30% less than Rob.
If Lucy saved $210, how much did Perry save?

Is Rob or Perry 100%? Why?

You can set either to be 100%.

eg.
1) Perry --> 100%, Rob --> 60%, Lucy --> 0.7 x 60% = 42%
42% --> $210, Perry --> 210/42 x 100 = $500

2) Rob --> 100%, Perry --> 100/60 x 100% = 500/3 %, Lucy --> 70%
70% --> $210, Perry --> 500/3 x 210/70 = $ 500

3) using ratio
Rob : Perry = 60:100 = 3:5
Rob : Lucy = 100 : 70 = 10 : 7
Rob : Perry : Lucy --> 30 : 50 : 21
Perry --> 50/21 x $210 = $500

cheers.

[ozora]

1.The number of basketballs was 3/5 of the number of footballs. In jan , 1/3 of the basketball and 1/3 of the football were sold. In feb,4 basketball n 4 footballs were sold. The number of basketballs left was 1/2 of the number of footballs. How many basketballs were there at first?


2.Andy, Bryan and calvin decided to share to buy a present. The total of Andy’s and Bryan’s to Calvin’s share was 7:2. The total of Bryan’s and. Calvin’s share to Andy’s share was 2:3. Andy paid $19 more than Bryan. Find the cost of the present.

Thanks for guiding in advance.

[ozora]

MathIzzzFun:

ozora:

need some guide in this questions.

Rob saved 40% less than Perry.
Lucy saved 30% less than Rob.
If Lucy saved $210, how much did Perry save?

Is Rob or Perry 100%? Why?

You can set either to be 100%.

eg.
1) Perry --> 100%, Rob --> 60%, Lucy --> 0.7 x 60% = 42%
42% --> $210, Perry --> 210/42 x 100 = $500

2) Rob --> 100%, Perry --> 100/60 x 100% = 500/3 %, Lucy --> 70%
70% --> $210, Perry --> 500/3 x 210/70 = $ 500

3) using ratio
Rob : Perry = 60:100 = 3:5
Rob : Lucy = 100 : 70 = 10 : 7
Rob : Perry : Lucy --> 30 : 50 : 21
Perry --> 50/21 x $210 = $500

cheers.

Thanks

[ozora]

Need guide in this question only: The number of basketballs was 3/5 of the number of footballs. In jan , 1/3 of the basketball and 1/3 of the football were sold. In feb,4 basketball n 4 footballs were sold. The number of basketballs left was 1/2 of the number of footballs. How many basketballs were there at first?


Thanks