This question basically asks for the LCM of 3 and 5, which is 3 x 5 =15
This is the answer: 15
Check : The first rectangle had 1/3 shaded; ( one in every three parts)
So for 15 parts altogether, 5 would be shaded ( 1/3 = 5/15)
The second rectangle had 2/5 shaded ( two for every five parts)
So for 15 parts altogether, 6 would be shaded (2/5 = 6/15)
21/2 is what you should get if you divide those two
A because, all the numbers multiplied by those factors equals their spot in the number
