Explanation:

Total savings of A and B = 50% of their total income
So, Total expenditure of A and B also will be equal to 50% of their total income
Average expenditure = Rs. 16000
So, Total expenditure = Rs. 32000 = 50% of their total income
So, Total income of A and B = Rs. (32000 * 2) = Rs. 64000
Alternate Method:-
Salary of A is 37.5% of the total salary of A and B.
Let the total salary of A and B = 16k
The Salary of A = (3/8) × 16k = 6k → Salary of B = 10k
B saves 60% of his salary and total savings of A and B is 50% of their total income.
Savings of B = 60% (10k) = 6k → Exp (B) = 4k
Total savings of A and B = 50% (16k) = 8k → savings (A) = 8k – 6k = 2k → Exp (A) = 2k
Their average expenditure is Rs 16000
Average expenditure of A and B = 4k = 16000 → k = 4000

Total salary of A and B = 16k = Rs 64000