A school has a 20% sale on all headphones. With this discount the price of headphones is $47 What was the orginal price of the pair of headphones​

Part a : solve -vp + 40 < 65 for v part b : solve 7w - 3r = 15 for r show your work .

Awater holding tank measures 105 m long, 50 m wide, and 8 m deep. traces of mercury have been found in the tank, with a concen- tration of 60 mg/l. what is the total mass of mercury in the tank? answer in units of kg.

At the county fair, the baxter family bought 6 hot dogs and 4 juice drinks for $12.90. the farley family bought 3 hot dogs and 4 juice drinks for $8.55. find the price of a hot dog and the price of a juice drink.