Respuesta :
Step 1: Create Equation: 12+15+x=55
Step 2: Solve it: you will get x=28
Step 3: You could check it by plugging your answer in.
Hope that helps!!!
Step 2: Solve it: you will get x=28
Step 3: You could check it by plugging your answer in.
Hope that helps!!!
Answer is A:
Check that the sum of the final answer, 12, and 15 is 55.
this makes sense b/c there must be 28 marbles (55 - 12 - 15 = 28) so 28 + 15 + 12 must = 55.