Q: There are 40 students in a class. If 1/10 are absent, 3/4 of the students who are present are in the classroom, and the rest are in the canteen, how many students are in the canteen?
A: Out of the 40, 40 x 1 / 10 = 4 students are absent. So, 40 - 4 = 36 students are present in school. Out of the 36, 36 x 3 / 4 = 27 students are in the classroom. This means, 36 - 27 = 9 students are in the canteen. The answer is 9.

Q: Venny spent $15000 on a used car which cost 40% of the original price. What was the original price of the car?
A: Let x be the original price of the car. Then 40% * x = $15000. Thus x = $15000 / 0.4 = $37500. The answer is 37500.

Q: Mike is feeding the birds at the park. He counts out the seeds as he throws them. He throws 20 seeds to the birds on the left. He throws twice as much to the bigger group of birds on the right. Some more birds flutter over to join the others for lunch and Mike throws 30 more seeds for them. If Mike has 30 seeds left to feed the last of the birds, how many seeds did Mike start with?
A:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
Mike started by throwing 20 seeds to the birds and then threw twice as many, 20 + 20(2) = 20 + 40. That totals to 20 + 40 = 60 seeds. He also threw 30 other seeds and had 30 left over, which means he started with 60 + 30 + 30 = 120 seeds. The answer is 120.