If 25a + 25b = 115, what is the average of a and b?

Answer: Option E

25a + 25b = 115
⇒ 25 (a + b) = 115
⇒ a + b = $$\frac{115}{25}$$
⇒ a + b = $$\frac{23}{5}$$
∴ Average of a and b
= $$\frac{a+b}{2}$$
= $$\frac{23}{5}$$ × $$\frac{1}{2}$$
= $$\frac{23}{10}$$
= 2.3