In a race of 200 m, B can give a start of 10 m to A and C can give a start of 20 m to B. The start that C can give to A in the same race is ?
Correct Answer: 29 m
B : A = 200 : 190
C : B = 200 : 180
$$\eqalign{ & = \frac{C}{A} \cr & = {\frac{C}{B} \times \frac{B}{A}} \cr & = {\frac{{200}}{{180}} \times \frac{{200}}{{190}}} \cr & = \frac{{200}}{{171}} \cr} $$
∴ C can give to A, a start of (200 - 171) m = 29 m
C : B = 200 : 180
$$\eqalign{ & = \frac{C}{A} \cr & = {\frac{C}{B} \times \frac{B}{A}} \cr & = {\frac{{200}}{{180}} \times \frac{{200}}{{190}}} \cr & = \frac{{200}}{{171}} \cr} $$
∴ C can give to A, a start of (200 - 171) m = 29 m