Answer & Solution
Answer: Option C
Solution:
$$\eqalign{
& \text{Average mark of biology} \cr
& = \frac{90+55}{2} \cr
& = \frac{145}{2} \cr} $$
Average of sum of Math first term & English first term
$$\eqalign{
& = \frac{100+70}{2} \cr
& = \frac{170}{2} \cr
& \therefore \text{Required ratio} \cr
& = \frac{145}{2} : \frac{170}{2} \cr
& = 29 : 34 \cr} $$
