Answer:
47.06 + d = 150
Explanation:
So she's planning to save 150 in total. She already saved 12.64. Her grandmother gave her three times as much as that (12.64 * 3=37.92). so an equation would be 12.64 + d + 37.92 - 3.50 = 150
(where d represents the amt. of money left she needs to earn.) If we add up 12.64 and 37.92, we get 50.56 - 3.50 + d = 150.
50.56 - 3.50 = 47.06, so now the equation is 47.06 + d = 150
Subtract: 150 - 47.06 = 102.94, so d = 102.94