Answer :
Say x = the number of items being purchased. Then we can write the equation, using seconds:
3x + 16 = 136
(3 seconds per item, plus 16 seconds to process payment, equals 136 seconds total.)
Subtract 16 from each side. Then divide both sides by 3.
3x + 16 = 136
(3 seconds per item, plus 16 seconds to process payment, equals 136 seconds total.)
Subtract 16 from each side. Then divide both sides by 3.