Question 4008
i can help with the first part....

ok.. first lets rite the question.... A = P + PRT and then let's plug in the givens...

70 = 50 + (50 x 1.2 x T)    now 50 x 1.2 = 60T so lets rewrite the problem...

70 = 50 + 60T  and now we are gonna subtract 50 from both sides and we get 

20 = 60T ..... now divide out the 60 on both sides and we get  20/60 and 60/60T and we get 

1/3 = T..... now just to be sure lets plug it in and see if it works...

A = 50 + (50 x 1.2 x .33)     

A = 70

Good to go???
Carl