krystal is comparing two internet service plans. Plan 1 cost $34.99 per month. Plan 2 costs $ 134.97 every 3 months. If krystal plans to stay with one service plan for 1 year which should she choose? how much will she save?

Plan 1 costs $34.99 per month.
For 12 months, it would cost 12 * $34.99 = $419.88

Plan 2 cost $134.97 for 3 months.
A year is 12 months, so it has 4 periods of 3 months.
In one year, this plan would cost 4 * $134.97 = $539.88

She should choose Plan 1.
She will save $539.88 - $419.88 = $120