Guys my teachers wanna make everything hard

six times a number decreased by ten is eight. find the number.
a) 2
b) 3
c) 4
d) 5

If an athlete can bike 6 miles in 25 minutes, how many miles will he bike in an hour and half if he continues to bike at the same rate?

Ineed with math stuff it involves graphs

Money off coupons have been circulated to 300 households. only 2/5 of these were redeemed (used) in the local supermarket to get a free shampoo. what fraction of coupons were unused? (ps: write how you got the answer)