Maths level 1

Question

last year tim spent 20% of his salary on rent , 1/5 of his salary on entertainment, 1/4 of his salary on living expenses. the rest he saved. he spent £4000 on entertainment. how much money did he save?

Answer 1

Recall that 20% = 1/5. Let f be the fraction of the money Tim saved. Then,

 

1/5 + 1/5 + 1/4 + f = 1

 

2/5 + 1/4 + f = 1

 

f = 1 - 2/5 - 1/4

 

f = 20/20 - 8/20 - 5/20, finding common denominator 20

 

f = 7/20

 

So, he saved 7/20 of his salary X.

 

We are told that he spent 4000 on entertainment, but entertainment represents 1/5 of his salary.

So, (1/5)X = 4000

Or X = 20,000

 

Therefore, he saved

(7/20)(20,000) = 7,000