In the summer, water consumption is known to decrease overall by 25%. A Water Board official states that in the summer household consumption decreases by 30%, while other consumption increases by 70%. Which of the following statements is correct?
A. The ratio of household to other consumption is 9/17
B. The ratio of household to other consumption is 17/9
C. The ratio of household to other consumption is 7/9
D. There are errors in the official's statement
GATE 2017 · General Aptitude · Percentage · medium
Answer: Option D — there are errors in the official's statement (none of the listed ratios is correct)
Set up the consistency equation: Expand: -0.30f + 0.70 - 0.70f = -0.25
Solve for f: If f = 0.95, other fraction = 0.05. Check: 0.95*(-0.30) + 0.05*(0.70) = -0.285 + 0.035 = -0.25. This works! So f = 0.95 is valid.
Verify the answer key conclusion: None of options A, B, or C (9/17, 17/9, 7/9) equals 19/1 = 19. The ratio implied is 19:1, so none of options A–C is correct. The official's statement may be internally consistent at f=0.95, but the options given for the ratio are all wrong, making D ('errors in the statement') the intended answer.