Mrs. Garcia pays her insurance quarterly at $378. How much does she pay in a year for her insurance?
Let's think: Since there are three months in a quarter, then there are 12 / 3 = 4 quarters in a year. So, Mrs. Garcia pays $378 x 4 = $1512 in a year for her insurance.. The answer is: 1512.

If you double a number and add 5 to the result, then that's 20 more than half of the original number. What's the original number?
Let's think: Let x be the original number. 2 * x + 5 = 20 + x / 2. 2 * x - x / 2 = 15. 4 * x - x = 30. 3 * x = 30. x = 10.. The answer is: 4.

36 liters of diesel fuel is worth €18. The tank of this pickup truck can hold 64 liters. How much does a full tank of diesel fuel cost?
Let's think: A liter of diesel costs 18 / 36 = 0.5 €. 64 liters of diesel fuel cost 0.5 X 64 = 32 €.. The answer is: 32.

A forester is planting trees. The forest already has 30 native trees. On Monday he triples the number of total trees in the forest by planting new trees. On Tuesday, he plants a third of the amount he planted on Monday. How many trees has the forester planted in total?
Let's think:
Let M be the number of trees he plants on Monday. On Monday the forest was three times larger from the trees that were originally there and the M trees: 3 * 30 = 30 + M trees. So, 90 = 30 + M. And, M = 60 trees. On Tuesday, he planted 60 trees / 3 = 20 trees. In total, he has planted 60 trees + 20 trees = 80 trees.. The answer is: 80.