Solution:Concept- Using concepts of linear equation in two variables the cost of a pineapple and cost of a watermelon can be determined. X spends Rs. 38 on these fruits. The cost of ‘m’ pineapples is Rs. m and the cost of ‘n’ watermelons is Rs. n. The total amount on these fruits is
Total amount on these fruits is,
Changing the value of n in the equation above,
Hence, option 3 is correct.