Lia =x Zane = x+20
equation 1/x + 1/x+ 20 = 1/4.95 LCD= 4.95 (x) (x+20) multiply both sides of the equation and cancel out
common factors
4.95 x + 990+ 4.95 x= X^2 +20x put all the terms on one side
0= x^2-79x-990
0=(x-90)(x+11)
x=90 ,x= -11
Lia takes 90 minutes to do the job alone and Zeno takes 90+20 minutes = 110 minutes to do the job alone.