99+69= 168
They spent 168 dollars in total
36 = 2² * 3²
84 = 2² * 3 * 7
Explanation:
Pf of 36 = 2 * 2 * 3 * 3 which then becomes 2 (to the power of 2) times 3 (to the power of 2)
Pf of 84 = 2 * 2 * 3 * 7 which then becomes 2 (to the power of 2) * 3 * 7
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