Step-by-step explanation:
x = earnings from the store
y = earnings from the college
x + y = 67,250
x = 3y + 1,250
now we use the identity of the second equation in the first equation :
(3y + 1,250) + y = 67,250
4y = 66,000
y = $16,500
x = 3y + 1,250 = 3×16,500 + 1,250 = 49,500 + 1,250 =
= $50,750