Q&A - P5 Math

[Oracle]

How about this:


There are some 20-cent and 50-cent coins in a piggy bank. The coins add up to $17.30. There are 6 more 20-cent coins than 50-cent coins. How many 50-cent coins are there in the piggy bank?

[MathIzzzFun]

Oracle:

How about this:


There are some 20-cent and 50-cent coins in a piggy bank. The coins add up to $17.30. There are 6 more 20-cent coins than 50-cent coins. How many 50-cent coins are there in the piggy bank?

make the number of coins same ie same number of 20-cent and 50-cent coins -- either add 6 more 50-cent coins or remove 6 20-cent coins

add 6 more 50-cent coins --> 6 x $0.50 = $3.00
Total amount of money = $ 17.30 + $3.00 = $20.30
1 set of 1x20-cent and 1x50-cent coins --> $0.70
$20.30 / $0.70 --> 29 sets of 1x20-cent and 1x50-cent coins

Number of 50-cents --> 29 - 6 = 23


remove 6 20-cent coins --> 6 x $0.20 = $ 1.20
Total amount of money --> $ 17.30 - $ 1.20 = $ 16.10
1 set of 1x20-cent and 1x50-cent coins --> $0.70
$16.10 / $0.70 --> 23 sets of 1x20-cent and 1x50-cent coins

Number of 50-cent coins = 23

cheers.

[Oracle]

Thanks MathIzzzFun, inspired by your workings, I managed to conceptualize the problem sum. Basically,


Total amount of money → $17.30
6 more 20¢ coins than 50¢ coins → (20c x 7) + 1x50¢ → $1.90
One set of 1x20¢ and 1x50¢ coins → $0.70
$17.30 - $1.90 = $15.40
$15.40 ÷ $0.70 = 22 sets of 20¢ and 50¢

Therefore, number of 50¢ coins
= twenty-two 50¢ + one 50¢
= 23

Thank you very much indeed.

[chloecube]

Borsche manufactures 3 cars daily while Percedes manufatures 2 more cars everyday. Even though Percedes started production 12 days later than Borsche, Percedes has now produced 14 more cars than Borsche.

a) how many cars did Borsche produce by Day 12?
b) how many days did Percedes take to produce 14 more cars than Borsche?

(no listing method)

[aiong]

Dear all


I need help on this question:-
Joshua counted the number of digits of all the page numbers in an encyclopedia. He found that a total of 1359 digits were used. How many pages were there in the book?

Thank you

[chloecube]

in a stadium, the number of girls is equal to the number of men. there are 252 females altogether, 7/9 of the children and 2/3 of the adults are females.

a) find the number of girls
b) find the difference in the number of children and adults

[MathIzzzFun]

chloecube:

in a stadium, the number of girls is equal to the number of men. there are 252 females altogether, 7/9 of the children and 2/3 of the adults are females.

a) find the number of girls
b) find the difference in the number of children and adults

Children --> 9 units
Girls --> 7 units
Boys --> 2 units
Men --> 7 units (1/3 of adults)
Women --> 14 units
Adults --> 21 units

Total females --> 7 units + 14 units = 21 units --> 252
1 unit --> 12

Number of girls --> 7 x 12 = 84
Difference in number of adults and children
--> 21 units - 9 units
= 12 units
= 12 x 12 = 144

cheers.

[MathIzzzFun]

chloecube:

Borsche manufactures 3 cars daily while Percedes manufatures 2 more cars everyday. Even though Percedes started production 12 days later than Borsche, Percedes has now produced 14 more cars than Borsche.

a) how many cars did Borsche produce by Day 12?
b) how many days did Percedes take to produce 14 more cars than Borsche?

(no listing method)

Borsche --> 3 cars/day
Number of cars produced by Borsche in 12 days --> 12 x 3 = 36 cars

To produce 14 more cars, Percedes must first catch up on the first 36 cars.
Total number of extra cars to be produced
= 36 + 14 = 50 cars

number of days Percedes take to produce 14 more cars than Borsche
= 50/2 = 25 (by day 37)

cheers.

[Aisikin]

in a stadium, the number of girls is equal to the number of men. there are 252 females altogether, 7/9 of the children and 2/3 of the adults are females.

a) find the number of girls
b) find the difference in the number of children and adults

Let the total number of Children be 9 units.
=> there are 7units of girl. Since the number of girls is same as the number of men, there will also be 7 units of men.
Men made up 1/3 of the adult, thus 2/3 of the adult is women, which is 14units.

7units of girls and 14units of women = 252 females => 1 unit = 12.

a) number of girls = 7 units x 12 = 84 girls.
b) total children is 9units = 9x12 = 108
total adult is 21units = 21x12 = 252
difference is 252-108 = 144.

[Jamesbond]

Thanks for ur help…MathIzzzFun regarding my last question…