A3. Two straight roads stand vertically on a horizontal base, $20 \mathrm{~m}$ apart from each other. The distance between their tops is $25 \mathrm{~m}$. How many meters is one road higher than the other?
(A) 5
(B) 12
(C) 13
(D) 15
(E) 32
A3. According to the Pythagorean theorem, $x^{2}=(25 \mathrm{~m})^{2}-(20 \mathrm{~m})^{2}$. The longer path is higher by $x=15 \mathrm{~m}$.