What's the fastest way to do these math problems?

GammaGrozza
Tue, 21 Jul 2009 18:25:19 +0000

P–Q–R-S—T (S is not placed to scale)
QS=10, PS=19. By looking at the above diagram, it shouldn’t be hard to realize that PQ=9, therefore PR is 18, therefore PT is 36. PT-PS=ST=36-19=17.

t=total time, in minutes. (t-1)*y= total cost after 1st minute. x=cost of first minute. So, x+y(t-1)=5.55, t-1=(555-x)/y, so t=[(555-x)/y]+1. Same thing you got, except I didn’t use actual values. Your way might be better, though.