HOW TO GET A SPECIFIC CELL TO CHOOSE BETWEEN 5 FIXED CELLS BASED ON 01 VARIABLE CELL

Question

C3 gets a value from another Tab of a values as follows: 3,5,12 and 15. I need G10 to see what the value of C3 is, and then decide which cell to use that is similar to the values in the B7(3), B10(5), B13(12), B16(15) Cells. However,G10 THEN need to add the values of either C7,C10,C13 or C16 INSIDE G10, BASED on the fixed values in the B Cells.