Answer:10 percent

Step-by-step explanation:

Let's calculate the gain percent of 3/4 of the mangoes based on the given information.

Total number of mangoes = 50

Number of mangoes with a 5% loss = 1/4 * 50 = 12.5 (rounded to 13 mangoes)

Number of mangoes without any loss = 50 - 13 = 37 mangoes

Now, let's calculate the total cost price (CP) and selling price (SP) of the mangoes.

CP of 50 mangoes = $1000 (given)

CP of 1 mango = 1000 / 50 = $20

Since the total gain percent is 10%, the selling price (SP) will be 110% of the total cost price (CP).

SP of 50 mangoes = 110/100 * $1000 = $1100

SP of 1 mango = 1100 / 50 = $22

Now, let's calculate the total cost price (CP) and selling price (SP) of the 37 mangoes without any loss.

CP of 37 mangoes = 37 * $20 = $740

SP of 37 mangoes = 37 * $22 = $814

The gain made on these 37 mangoes = SP - CP = $814 - $740 = $74

Now, let's calculate the gain percent for these 37 mangoes.

Gain percent = (Gain / CP) * 100

Gain percent = ($74 / $740) * 100

Gain percent = 10%

Therefore, the gain percent for 3/4 of the mangoes (37 mangoes) is 10%.