This question utilizes combining like terms and common denominators. First you have to convert both terms including "a" to have a denominator of 8. You would do this by multiplying both the numerator, and the denominator by the same value. This value in the case of would be 2, and in the case of the value would be 2. This would result in the equation: . Then simply combine like terms to get your final answer.
To get the result we can use knowledge that reading is 2 times longer than HW. To find this value we just have to multiply 42 times 2 so 40*2=80 Its 1 hour and 20 min - its the result