[Question]: Martha has 11 butterflies in her collection. She has twice as many blue butterflies as yellow butterflies. The rest of her butterflies are black. If Martha has 5 black butterflies, how many blue butterflies does she have?
[Answer]: Martha has 11 - 5 = 6 blue and yellow butterflies. Martha has 6 / 3 = 2 yellow butterflies. Martha has 2 * 2 = 4 blue butterflies.
So the answer is 4.

[Question]: During one day, there are 4 boat trips through the lake. The boat can take up to 12 people during one trip. How many people can the boat transport in 2 days?
[Answer]: During each boat trip, there can be 12 people onboard, so during 4 boat trips, there can be 4 * 12 = 48 people in total. During two days the boat can transport a total of 48 * 2 = 96 people.
So the answer is 96.

[Question]: Elise is buying more dog food. She buys a 15kg bag then another 10kg bag, and she now has 40kg of dog food. How many kilograms of dog food did Elise already have?
[Answer]:
Elise has bought a total of 15 kg + 10 kg = 25kg of dog food. This means she already had 40 kg 25 kg = 15kg of dog food.
So the answer is 15.