Jerry spent 1/5 of his allowance on a book and 3/8 of the remainder of his allowance for a pen. Jerry remained with $12.00 Calculate

Question

Jerry spent 1/5 of his allowance on a book and 3/8 of the remainder of his allowance for a pen. Jerry remained with $12.00 Calculate a. Jerry's allowance, b. the cost of the book, c) the cost of the pen

Answer 1

Let allowance be x

cost of book = 1/5 of x

cost of pen = 3/8 of 4/5 of x

Balance in hand = 12

Therefore allowance,

x = (1/5)x + (3/8)(4/5)x + 12

x - (1/5)x - (3/10)x = 12

(10x- 2x -3x)/10 = 12

5x = 120

x = $24

Cost of book = (1/5) x 24 = 4.8

Cost of pen = (3/10) x 24 = 7.2

Answer 2

So, $12 is 5/8 of 4/5 of his allowance.

 

(5/8)(4/5)a = 12

(20/40)a = 12

2(1/2)a = 12(2)

a = 24

 

(1/5)24 = 4.8

 

(3/8)(24 - 4.8) = (3/8)(19.2) = 7.2

 

The book was $4.80 and the pen was $7.20.