Set C is the set of two-digit even numbers less than 56 that are divisible by 5

[math_celebrity]

Two digit Numbers less than 56:
{10, 11, 12, ..., 55}

Two Digit Even Numbers of that Set:
{10, 12, 14, ..., 54}

Two Digit Even numbers Divisible by 5
C = {10, 20, 30, 40, 50}

Note: Even means you can divide it by 2 with no remainder. Divisible by 5 means the number ends in 5 or 0. Since it is even numbers only, end in 0.