Explanation:

Correct option 1: 26.67%
Given:

A person marks the price of his car 50% above the cost price.

He gives a discount of 8% and earns a profit of 10%.

Concept used:

Final percentage change after two successive increments of A% and 8% = (A+B+ AB/100)%

Calculation:

According to the concept,

50-B - (50B)/100 = 10 (Here, 8% discount is considered as a negative mark-up/increment)

=>  50-B -B/2 = 10

= 3B/2 = 40

=> B = 80/3

B ≈ 26.67