The cost of a new laptop is $750 which genorates a sales tax of$37.50 what is the sales tax rate

How long must $542 be invested at a rate of 7% to earn $303.52 in interest? in a easier way

Lizette is training for a marathon. at 7: 00 she left her house and ran until 8: 30, then she walked until 11: 30. she covered a total distance of 18 miles. her running speed was six miles per hour faster than her walking speed. find her running and walking speeds in miles per hour.

How much is $1200 worth at the end of1 year,if the interest rate is 5.5% is compounded quarterly.