Daniel, Riordan and Clayton collected pens in the ratio of 9 : 10 : 4. After Clayton gave ³₅ to Daniel and Riordan, Clayton had 166 less pens than Daniel. The number of pens that Riordan had increased by 15%. How many pens did Daniel and Clayton have in the end?

	Daniel	Riordan	Clayton
Before	9 u	10 u	4 u
Change	+ 0.9 u	+ 1.5 u	- 2.4 u
After	9.9 u	11.5 u	1.6 u

Number of pens that Clayton gave to Daniel and Riordan
= ³₅ x 4 u
= 2.4 u

Number of pens that Riordan received from Clayton
= ¹⁵₁₀₀ x 10 u
= 1.5 u

Number of pens that Daniel received from Clayton
= 2.4 u - 1.5 u
= 0.9 u

Number of less pens that Clayton had less than Daniel
= 9.9 u - 1.6 u 
= 8.3 u

8.3 u = 166

1 u = 166 ÷ 8.3 = 20

Number of pens that Daniel and Clayton had
= 9.9 u + 1.6 u
= 11.5 u
= 11.5 x 20
= 230

Answer(s): 230