Question

if 1/r=1/r1+1/r2, find r if r1=3/4 and r2=2/3, giving your answer as a fraction

Answer 1

1/r = 1/$\frac{3}{4}$ + 1/$\frac{2}{3}$

that is 1/r = 4/3 + 3/2 = ((4*2) + (3*3)) / (3*2)

1/r = 17/ 6

r= 6/17