I do not know how to process this i keep getting 122

Question

A small circus has an act with elephants and riders. In all there are 50 eyes and 72 feet. What is the total number of elephants plus riders?

Answer 1

e = number of elephants with 2 eyes and 4 feet each

r = number of riders with 2 eyes and 2 feet each

Eyes equation:

2e + 2r = 50 ⇒ e + r = 25 ⇒ e = 25 - r

Feet equation:

4e + 2r = 72 ⇒ 2e + r = 36

2(25 - r) + r = 36

r = 14

e = 25 - 14 = 11

Test the answers.