Final answer:
To solve this problem, we use the formula for direct variation and solve for the constant of variation. Then, we substitute the given value of a to find the value of b.
Step-by-step explanation:
To solve this problem, we can use the formula for direct variation: a = kb, where k is the constant of variation. From the given information, we have the equation: 5 = 18k. Solving for k, we find that k = 5/18. Now, we can use this value of k to find the value of b when a = 22: 22 = (5/18)b. Solving for b, we get b = 88.