Question

A girl read 3/8 of her book one day and 2/5 the next day. How much was there left to read?

Answer 1

9/40 of the book was left to read

Explanation:

Required to find the fraction of remainder of the book:

first we need to find the (LCM) lowest common multiple so both fractions can have common denominator in order to complete addition or subtraction.

`(3)/(8 ) + (2)/(5)`

Look at the denominators, we see there is 8 and 5 so that means we have to list the multiples of both numbers until a common is found.

multiples of:

8 = 8, 16, 24, 32, 40

5 = 5, 10, 15, 20, 25, 30, 35, 40

from this we can distinguish that the LCM is 40.

Next we need to multiply each numerator of the fraction by the number of times it took for the denominator to reach the LCM.

It took 8 five multiples to reach the LCM so therefore its new numerator will be 3×5 = 15

`(5)/(8) to \: give (15)/(40)`

It took 5 eight multiples to reach the LCM so therefore its new numerator will be 2×8 = 16

`(2)/(5) to \: give \: (16)/(40)`

finally we can add but values together and subract from the whole to find the remainder.

`(15)/(40) + (16)/(40) = (31)/(40)`

in total she read 31/40 of the book.

`(40)/(40) - (31)/(40) = (9)/(40)`

and the remainder which she did not read was 9/40