A total of 252 silver pens and white pens are in a container. The ratio of silver pens to white pens was 2 : 5. Some gold pens and blue pens were put into the container. For every 9 white pens that were already in the container, 5 blue ones were added. Then, the final number of silver pens and gold pens was ⁴₇ the final number of white pens and blue pens. Find the total number of gold and blue pens.

Gold pens	Silver pens	White pens	Blue pens
	2x9	5x9
		9x5	5x5
4x10		7x10
22 u	18 u	45 u	25 u

The number of white pens is repeated.  Make the number of white pens the same.  LCM of 5 and 9 is 45.

The total number of white pens and blue pens is repeated.  Make the total number of white and blue pens the same.  LCM of 70 and 7 is 70.

Total number of silver pens and white pens
= 18 u + 45 u
= 63 u

63 u = 252

1 u = 252 ÷ 63 = 4

Total number of gold and blue pens
= 22 u + 25 u
= 47 u
= 47 x 4
= 188

Answer(s): 188