Math sucks help please <333!!!!!!!!!!! thanks?

Question

mary went to lunch. Bill was $10.75. Left 15% tip. what is total cost?

alex bought computer originally $1,500. sale 15%. tax 7.5%. total?

please show step by step work. thanks ure helping my summer <333

Answer 1

10.75 x 115% = $12.36    

Note: the 15% is an additional cost which is why I add 115%

1500 x 85% x107.5% = $1370.63

Note: Since it&#039;s sale you deduct 15%.  I did that by simply multiplying it by 85% then the sales tax is an addition of 7.5% or 107.5%

Answer 2

10.75 x .15 = $1.61 tip so 10.75+1.61 = $12.36

1,500 x .15 = 225 off so price is now 1,275 then 1,275 x .075 = $95.63 tax so 1,275 + 95.63 = $1,370.63 is final price

hope I helped

Answer 3

1) 10.75 +15% = $12.37

2)  1500 -15% = 1275 +7.5% =$1370.63