Weekly Allowance

[HPengineer]

Having received his weekly allowance, John spent 3/5 of his allowance at the arcade. The next day he spent one third of his remaining allowance at the toy store, and then spent his last $0.80 at the candy store. What is John's weekly allowance?

a.) 2.40
B.) 3.00
c.) 3/20
D.) 3.60
E.) 4.80

This problem is really pissing me off.. 3 months of solid prep and still getting problems like this wrong.. ready to give up...


My incorrect attempt..

I tried to find the fraction that was left out of 1 after the deductions then multiply by X and set = .8

Something like this 1 - (3/5) = 2/5 then take 1/3 of the 2/5 which = 2/15

then i did X(2/15) = .8

Can someone please explain...

[shovan85]

IMO B
The mistake is x(2/15) = 0.8
actually 0.8 is remaining after x(3/5) + x(2/15)

so x(1- 11/15) = 0.8
x = 0.8 *(15/4) = 3

[HPengineer]

your answer is correct and your explanation is clear. Thanks