Question

The area between the two isohyetes 45 cm and 55 cm is $100{\text{km}}^2$ and that between 55 cm and 65 cm is $150{\text{km}}^2$. What is the average depth of annual precipitation over the basin of $250{\text{km}}^2$

• A. 50 cm
• B. 52 cm
• C. 56 cm
• D. 60 cm

Answer 1

The correct option is C 56 cm

Average depth of annual precipitation

$=\frac{\left(\frac{45+55}{2}\right)\times 100+\left(\frac{55+65}{2}\right)\times 150}{100+150}=56\text{cm}$