She can tip 90 waiters from her 90.00 tip.
5.00 / 5 waiters = 90.00 / x
5.00x = 90.00 (5)
5.00x = 450
5.00x / 5.00 = 450 / 5.00
x = 90 waiters.
or 5.00 to 5 waiters is equal to 1.00 for every waiter. thus, a $90.00 tip can tip 90 waiters for $1.00 each.