Yen and Nora collected seashells. Yen gave 30% of her seashells to Nora and as a result, Nora's seashells increased by 10%. If Yen had 28 seashells left, find the number of seashells Nora should give to Yen in the end so that both had an equal number of seashells.

	Yen	Nora	Comparing the change in Nora's seashells
Before	10x1 = 10 u		10x3 = 30u
Change	- 3x1 = - 3 u	+ 3x1 = + 3 u	+ 1x3 = + 3 u
After	7x1 = 7 u		11x3 = 33 u

30% = ³⁰₁₀₀ = ³₁₀
10% = ¹⁰₁₀₀ = ¹₁₀

The increase in the number of seashells that Nora had is repeated.  Make the increase in the number of seashells that Nora had the same. LCM of 3 and 1 = 3

7 u = 28

1 u = 28 ÷ 7 = 4

Number of seashells that Nora had more than Yen in the end
= 33 u - 7 u
= 26 u

Number of seashells that Nora should give to Yen so that both had an equal number of seashells in the end
= 26 u ÷ 2
= 13 u
= 13 x 4
= 52

Answer(s): 52