Jenson and Riordan gave away the same number of erasers. Jenson gave away ³₅ of his erasers while Riordan gave ⁴₉ of his erasers away. Given that Jenson had 21 erasers less than Riordan at first, how many erasers did Jenson have at first?

	Jenson	Riordan
Before	5x4 = 20 u	9x3 = 27 u
Change	- 3x4 = - 12 u	- 4x3 = - 12 u
After	2x4 = 8 u	5x3 = 15 u

The number of erasers that Jenson and Riordan gave away is the same.  Make the number of erasers that Jenson and Riordan gave away the same. LCM of 3 and 4 is 12.

Number of erasers that Jenson had at first = 20 u
Number of erasers that Riordan had at first = 27 u

Number of erasers that Jenson had less than Riordan at first
= 27 u - 20 u
= 7 u

7 u = 21

1 u = 21 ÷ 7 = 3

Number of erasers that Jenson had at first
= 20 u
= 20 x 3
= 60

Answer(s): 60