The bar graph given below shows the number of mobile phones sold by the given 5 brands in a month.

A = Total number of mobile phones sold by brand X and Y.
B = Total number of mobile phones sold by brand Z and U.
What is the value of A : B?

Given:
A = Total number of mobile phones sold by brand X and Y.
B = Total number of mobile phones sold by brand Z and U.
Solution:
Calculate the sum of sales for X and Y to find A.

A = X + Y = 320 + 290 = 610 
Calculate the sum of sales for Z and U to find B.

B = Z + U = 410 + 350 = 760 
Determine the required ratio.
Ratio = 610 : 760 = 61 : 76
Final Answer
So the correct answer is (a)