From the question, it is mentioned that the remaining mangoes (M x 3/5) are 36 more than the remaining durians (D × 1/3).

This gives you an equation:

D x 1/3 + 36 = M x 3/5

Multiply all sides by 15 to remove denominators:

5D + 540 = 9M

Meanwhile, the total number of fruits is 130, means

D + M = 130

If you multiply all by 5,

5D + 5M = 650

Now you have 2 equations, and notice both have the same number (5D). If you subtract the second equation from the first equation (right side - right side = left side - left side), you get:

5D + 540 - 5D - 5M = 9M - 650

Simplify: 1190 = 14M
M = 85

Now that you figure out what M is, you can find D to be 130-85 = 45

Since the question asks for the fruits left, it would be
1/3 x 45 + 3/5 x 85
= 15+51
= 66

Check through each step slowly and make sure you understand the methods. Hope this helps!