A total of 196 purple notebooks and blue notebooks are in a container. The ratio of purple notebooks to blue notebooks was 2 : 5. Some black notebooks and pink notebooks were put into the container. For every 7 blue notebooks that were already in the container, 4 pink ones were added. Then, the final number of purple notebooks and black notebooks was ²₅ the final number of blue notebooks and pink notebooks. Find the total number of black and pink notebooks.

Black notebooks	Purple notebooks	Blue notebooks	Pink notebooks
	2x7	5x7
		7x5	4x5
2x11		5x11
8 u	14 u	35 u	20 u

The number of blue notebooks is repeated.  Make the number of blue notebooks the same.  LCM of 5 and 7 is 35.

The total number of blue notebooks and pink notebooks is repeated.  Make the total number of blue and pink notebooks the same.  LCM of 55 and 5 is 55.

Total number of purple notebooks and blue notebooks
= 14 u + 35 u
= 49 u

49 u = 196

1 u = 196 ÷ 49 = 4

Total number of black and pink notebooks
= 8 u + 20 u
= 28 u
= 28 x 4
= 112

Answer(s): 112