Tommy has 13 items in his pencil case. The pens are twice as many as the pencils and there's one eraser. How many pencils are there? Give the rationale and then the answer.
Let's think step by step. There are 13 items - 1 eraser = 12 pens and pencils. There are 12 items / 3 = 4 pencils.. The answer is: 4.

The big fashion show is being planned for next week. The show includes runway models strutting up and down the runway wearing designer clothing in front of an audience. There are two parts to the show: evening wear and bathing suits. It takes a model 2 minutes to walk out to the end of the runway and back, and models take turns, one at a time, walking the runway up and back, while wearing different clothes. If there are 6 models in the show, and each model will wear two sets of bathing suits and three sets of evening wear clothing during the runway portion of the show, how long will it take, in minutes, to complete all of the runway trips during the show? Give the rationale and then the answer.
Let's think step by step. 6 models wearing 2 sets of bathing suits, or a total of 6 * 2 = 12 trips wearing bathing suits. 6 models wearing 3 sets of evening wear, or a total of 6 * 3 = 18 trips wearing evening wear clothes. Altogether, there will be 12 + 18 = 30 trips up and down the runway. At 2 minutes per trip, all of the trips will take 30 * 2 = 60 minutes to complete.. The answer is: 60.

Leah bought 3 boxes of birdseed. When she went to put them away, she discovered that she already had 5 boxes in the pantry. Her parrot eats 100 grams of seeds each week and her cockatiel eats 50 grams of seeds in a week. If each box of birdseed contains 225 grams, for how many weeks can she feed her birds without going back to the store? Give the rationale and then the answer.
Let's think step by step. In a week, her birds eat a total of 100 grams + 50 grams = 150 grams of seed each week. Leah has a total of 3 + 5 = 8 boxes of birdseed. The boxes of birdseed contain a total of 8 * 225 grams = 1800 grams. This is enough birdseed to feed her pets for 1800 / 150 = 12 weeks.. The answer is: 12.