(b) Any number is divisible by 4, if the last two digits of that number is also divisible by 4.
Now, 2-digit numbers which is divisible by four
={16,36,44,48,56,64,68,84,88,96}
∴ Number of ways = 10
Total 3-digit numbers which is divisible by four= 7 x10 = 70
∴Required number of ways = 70 +10 = 80