Question 905102
1/b+1/c=1/4
1/12+1/c=1/4
rate for A alone 12
rate for A & c together 4
1/a+1/c=1/x
1/12+1/c=1/4
1/c=1/4-1/12
1/c=12/48-4/48
1/c=8/48
1/c=1/6
c=6
rate for c alone 6
check
1/12+1/6=1/4
6/72+12/72=1/4
18/72=1/4
ok


Note we have extra info. We don't need the info about A unless you left something out