At Blooming Gardens nursery, they are currently running the following promotion: Buy three trees of the same kind at the regular price and get the fourth at 80% off. Jocelyn is needing some trees for her backyard and decided to buy four red oak trees using the promotion. The regular price for a red oak tree is $390.00. Based on a tax rate of 8.25%, Jocelyn ended up saving $ by using the promotion.

Regular price is

4 times 390=1560

tax=8.25%

1560 times 0.0825=128.7

add that

1560+128.7=1688.7 is price if didn't use promotion

if deal then

3 normall trees+1 that is 80% off

find the 4th tree

390 times 0.80=312 off

390-312=78

3 normal trees+78=3 times 390+78=1248

find the tax

0.0825 times 1248=102.96

add

1248+102.96=1350.96

compare prices

1688.7 no promotion

1350.96 with promotion

subtract

1688.7-1350.96=337.74

she saved $337.74