Jane travelled 4/7 as many miles on foot as by water and 2/5 as many miles on horseback as by water. If she covered total of 3036 miles, how many miles did she travel on foot ?

Answer: Option B

Suppose Jane travelled x miles by water,
$$\frac{4x}{7}$$ miles on foot and $$\frac{2x}{5}$$ miles on horseback.
Then,
$$\begin{array}{rl}& \iff x+\frac{4x}{7}+\frac{2x}{5}=3036\\ & \iff \frac{69x}{35}=3036\\ & \iff x=\left(\frac{3036\times 35}{69}\right)\\ & \iff x=1540\end{array}$$
∴ Distance travelled on foot :
$$\begin{array}{rl}& =\left(\frac{4}{7}\times 1540\right)\text{ miles}\\ & \text{ = 880 miles}\end{array}$$