6. A home repair crew charges seventy-five dollars per day plus two hundred fifty-five dollars for each hour the crew works. One day the
crew works c hours and charges a total amount of one thousand,
six hundred five dollars. How many hours does the crew work?
Math

At the beginning of 1974/75,2 years a man invested #2000 in a bank at 12.5% compound interest, if it degree #650 at the end of each two years to pay his son's school fees, after payment of interest to pay his son's school fees, how much did he have left at the beginning of the 1978/79 school year?

What is the length of the segment, endpoints of which are intersections of parabolas y=x2? 11 4 x? 7 4 and y=? 7 8 x2+x+ 31 8 ?

If np3 /nc2 = 6, find the value of n