The house cost 320,000 * 1.5 = $480,000. So it is worth 480,000 - 320,000 = $160,000 more than other houses. So the profit is 160,000 - 100,000 = $60,000 more.
The answer: 60000
Reverse engineering the question: The cost of building a certain house in an area is 100,000 more than the construction cost of each of the houses in the area. But it sells for 1.5 times as much as the other houses, which sell at $320,000 each. How much more profit is made by spending the extra money to build?

She eats 3 beignets every morning and there are 7 days in a week so she eats 3 * 7 = 21 beignets in a week. She eats 21 beignets in a week so over 16 weeks she will have eaten 21 * 16 = 336 beignets.
The answer: 336
Reverse engineering the question: Sandra eats 3 beignets every morning. How many beignets will she eat in 16 weeks?

The 5th graders planted 30 x 2 = 60 trees. Thrice the number of trees planted by the 5th graders is 60 x 3 = 180. So, the 6th graders planted 180 - 30 = 150 trees. Therefore, they planted a total of 30 + 60 + 150 = 240 trees.
The answer: 240
Reverse engineering the question: A school does a yearly tree planting activity. This year, the 4th graders planted a total of 30 trees while 5th graders planted twice as many. The 6th graders planted 30 fewer than thrice the number of trees planted by the 5th graders. How many trees did they plant altogether?

After spending money on a shirt, Lily had $55 - $7 = $48 left. She spent $7 x 3 = $21 on another store. Therefore, she only has $48 - $21 = $27 left on her account.
The answer: 27
Reverse engineering the question:
Lily had $55 in her account. She spent $7 on a shirt. She then went to another shop and spent thrice as much as she spent on a shirt. How much money is left in Lily's account?