Q&A - P5 Math

[MathIzzzFun]

TulipisPink:

Q: A farmer had a square field with an area of 57600 sq meter. He planted a tree at the four corners and some along the sides of the field. Each tree was planted 20 m from the next. How many trees were planted on one side of the field?

Hi

each side of the square field --> sqrt (57600) = 240 m
240 / 20 = 12 gaps
Number of trees on one side = 12 + 1 = 13

cheers.

[TulipisPink]

You are fantastic good! Thanks!

[TulipisPink]

HI MathIzzzfun, Thanks a zill ! You had coloured my white hairs! ha ha…

[TulipisPink]

Hi tianzhu

Thanks for the answer… but we are still very confuse abt this sum.

[tianzhu]

TulipisPink:

Hi tianzhu

Thanks for the answer.. but we are still very confuse abt this sum.

Hi

Since (J+A) is repeated in both sets of ratios, we shall make the number of units for (J+A) the same so as to enable us to make a comparison.

The total units showing the amount of money J and A had is 9 units.

For the second set of ratio, the total units showing (J+A)’s amount of money is 7 units (6+1).

A common multiple of 7 and 9 is 63.

Best wishes

[MathIzzzFun]

TulipisPink:

HI MathIzzzfun, Thanks a zill ! You had coloured my white hairs! ha ha...

haha.. I can start a natural hair restoration salon!

cheers.

[cimman]

TulipisPink:

Hi parents

Could you help to solve this maths question? Thanks.

Pupil B, J and A shared some money. The ratio of B's money to the total of J's and A's money is 4:9. A's share was 6 times J's. B had $95 more than J. How much money had A?

if you don't mind using simultaneous equations, here's a solution:
http://i47.tinypic.com/2v0d7v6.png\">

[Udon]

Appreciate your help, can someone teach me how to break down the question n analyze... :imdrowning:


Q1

Kenny has 1.4 times the number of pens Sarah has. When Sarah gives
144 pens to Kenny, the ratio of the number of pens she has to the number of pens Kenny has is 1:3. How many pens must Kenny give back to Sarah so that she will have twice as many pens as him?
(Hint: Change the decimal to a fraction and then to a ratio)


Q2

David and Sally each have some money. If David spends $38, the ratio of his money to Sally's money will become 2:5. If Sally spends $38, the ratio of David's money to her money will become 8:13. How much money does each child have?

[tianzhu]

Udon:

Appreciate your help, can someone teach me how to break down the question n analyze... :imdrowning:


Q1

Kenny has 1.4 times the number of pens Sarah has. When Sarah gives
144 pens to Kenny, the ratio of the number of pens she has to the number of pens Kenny has is 1:3. How many pens must Kenny give back to Sarah so that she will have twice as many pens as him?
(Hint: Change the decimal to a fraction and then to a ratio)


Q2

David and Sally each have some money. If David spends $38, the ratio of his money to Sally's money will become 2:5. If Sally spends $38, the ratio of David's money to her money will become 8:13. How much money does each child have?

Hi

Q1

The total number of units stays the same before and after.

At first
Kenny ------ 7 units
Sarah ------ 5 units.

When Sarah gives 144 pens to Kenny, the ratio of the number of pens she has to the number of pens Kenny has is 1:3.

Kenny ------ 3 units ------- 9 units
Sarah ------ 1 unit ------- 3 units

5 – 3 -------- 2
2 units ------- 144
1 unit ------- 72

How many pens must Kenny give back to Sarah so that she will have twice as many pens as him?

Kenny ------ 1 unit ------- 4 units
Sarah ------ 2 units ------- 8 units

9 - 4 ------ 5

72*5 ------- 360.

Q2

The total number of units stays the same in the two scenarios.

If David spends $38, the ratio of his money to Sally's money will become 2:5.

David:Sally ------- 2 : 5 (7) ------- 6:15 (21)

If Sally spends $38, the ratio of David's money to her money will become 8:13.

David:Sally ------- 8 : 13 (21)

2 units ------- 38
1 unit ------- 19

David ------- 8*19 --------152
Sally -------- 15*19 -------- 285

Best wishes

[Udon]

Thanks for the reply, but i do not understand how to calculate


Kenny....1 unit become 4 units
Sally......2 units become 8 units

------------------------------------------------------------------------------------------
How many pens must Kenny give back to Sarah so that she will have twice as many pens as him?

Kenny ------ 1 unit ------- 4 units
Sarah ------ 2 units ------- 8 units

9 - 4 ------ 5

72*5 ------- 360.