Q&A - PSLE Math

[Ender]

A fruit seller packed some oranges into 22 big carton boxes and 8 small carton boxes. There were 14 more oranges in a big carton box than in a small box. The ratio of number of oranges packed into big carton boxes to the number of oranges packed into small carton boxes was 3:1 . How many oranges did the fruit seller pack altogether?

Number of oranges in small carton = 8u
Number of oranges in big carton = 22(u+14) = 22u + 308

8u : 22u + 308 =>1 : 3
8u/(22u+308) = 1/3
Cross mulitply
24u = 22u + 308
2u = 308
u = 154

Total = 8u + (22u + 308) = 4928

[COOKIE64]

Please help

Kathy had 7 bags of rice at first. Then she bought a bag of rice with the mass of 24.9 kg and another bag of rice with mass of 17.6 kg . As a result , the average mass of the bags of rice increased by 2.5 kg what was the total mass of the 9 bags of rice?

[NerdyMath]

Mr Tan is (8k+10) years old now. How has two children , Rosalynn and David . Mr Tan is twice as old as Rosalynn now. David is 2k years younger than Rosalynn. How old will Mr Tan be when David turns 18 years old?

MR TAN -> 8K+10
ROSALYNN -> 4K+5
DAVID -> 2K+5

This is a constant different question.

Difference in age ->8K+10-2K+5 = 8K-2K + 10-5
= 6K+5

As the difference will always be 6k+5, we can say that if David is 1 year old, Mr tan will be 6K+5 years older than him, if David is 2 years old, Mr tan will still be 6K+5 years older than him, so when David is 18 years old, Mr tan will still be 6K+5 older than him.

18+6K+5= 6k+23 years old

[PlayfulFairy]

Please help! Thanks!
At a sale, Mr Lim bought 10 mugs of the same kind. His sister bought 8 such mugs. She also bought 3 towels at $2.50 each. Altogether, she spent $2.30 less than Mr Lim. What was the total amount of money Mr Lim and his sister spent?

[Ender]

Hi , the answer is 6K+ 23 years old Mr tan will be

After seeing Nerdymath's solution. I understood the the answer.

[COOKIE64]

Ok Thanks to all for helping me

[Ender]

Please help with these Q

Mrs Tan is 40 years old and her son is twice her daughters' sage. Mrs Lim will be thrice her Sons's age when her daughter is 12 years old .how old will Mrs Lim be when her 2 children's combined age equals to her age ?

Now,
Lim = 40 yrs
Son =2d
Daugther =d


When the daughter is 12 years old, number of years passed is (12-d) years
Daughter = 12
Son = 12 + d , Constant difference
Lim = 36 + 3d(Triple of Son) or 40 + (12 -d)

3d + 36 =52 - d
4d = 16
d = 4
Son = 8 , 2 times of daughter.

Let the number of years pass to be 'u'
(Daughter + u) + (Son +u) = (Mrs Lim + u )
(4+u) +(8+u) = (40+ u)
12 + 2u = 40 + u
u = 28

In 28 years time

Edit note: The answer is 68 years old, from 40 +28

[NerdyMath]

Please help

Kathy had 7 bags of rice at first. Then she bought a bag of rice with the mass of 24.9 kg and another bag of rice with mass of 17.6 kg . As a result , the average mass of the bags of rice increased by 2.5 kg what was the total mass of the 9 bags of rice?

9* 2.5kg=22.5kg
24.9kg+17.6kg=42.5kg
42.5kg-22.5kg=20kg
20kg/2=10kg
10kgx7=70kg
70kg+42.5kg=112.5kg

Solved by DS.

[NerdyMath]

Ok Thanks to all for helping me

You're welcome! DS is very happy to help!

[SAHMom]

Please help! Thanks!
At a sale, Mr Lim bought 10 mugs of the same kind. His sister bought 8 such mugs. She also bought 3 towels at $2.50 each. Altogether, she spent $2.30 less than Mr Lim. What was the total amount of money Mr Lim and his sister spent?

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