The number a is 40, which is 10 more than 3 / 5 of the number B. find the number B. (use equation solution)

The number a is 40, which is 10 more than 3 / 5 of the number B. find the number B. (use equation solution)

Let B be X
 
5 / 3x + 10 = 40
 
3 / 5 x = 30
 
X = 30 △ 3 / 5
 
x=50