Answer:
28 people :)
Step-by-step explanation:
step 1: output value is 70
step 2: represent the unknown value with x
step 3: step 1 above, 70 = 100%
step 4: similarly, x = %40
step 5: this results in a pair of simple equations, 70 = 100% , x = 40%
step 6: by dividing equation 1 by equation 2 and noting that both the RHS (right hand side) of both equations have the same unit (%); we have 70/x = 100%/40%
step 7: again, the reciprocal of both sides gives x/70 = 40/70 --> x = 28
hope this helped :)