Correct Answer: 60

Solution : Given: On a certain date, Pakistan had a success rate of 60% against India in all the ODIs played between the two countries. They lost the next 30 ODIs in a row to India, and their success rate came down to 30%.
Let the total number of ODIs be 10$x$.
Pakistan had a success rate of 60% ⇒ They won (10$x$ × $\frac{60}{100}$) = 6$x$ matches.
Losing the next 30 ODIs, their success rate came down to 30%.
So, the total number of matches = (10$x$ + 30)
Now, 6$x$ = (10$x$ + 30) × $\frac{30}{100}$
⇒ 6$x$ × $\frac{100}{30}$ = 10$x$ + 30
⇒ 20$x$ = 10$x$ + 30
⇒ 10$x$ = 30
⇒ $x$ = 3
Therefore, the total number of ODIs played between the two countries = (10 × 3) + 30 = 60
Hence, the correct answer is 60.