My logical thinking would go like this:
You got 31 people, so 10 will sit at the table,
leaving 21 to sit on blankets.
Each blanket will seat 3, so we need 7 blankets.
End of problem!
What's all that other nonsense ?
Which strategies can be used to solve this problem?
Colin invited 31 people to the picnic. He can fit 10 people at his picnic table and the rest will sit on blankets. Each blanket can hold 3 people. How many blankets does Colin need so that everyone has somewhere to sit?
Choose all answers that are correct.
A. Use logical reasoning.
Start with 31 people, subtract 10 people who will sit at the picnic table, that leaves 21 people. Keep subtracting 3 people until you get to 0. Count how many times you subtracted 3 people.
B. Work backward.
Start with 0 and keep adding 3 until you get to 30. The 1 that is left is the 1 table. The number of times you added 3 is the number of blankets.
C. Draw a diagram.
Ten people at one table, 3 people on a blanket, 3 people on a blanket, 3 people on a blanket, 3 people on a blanket, 3 people on a blanket, 3 people on a blanket, 3 people on a blanket. Count the number of blankets.
D. Translate into an equation.
31 – 10 + 3 + 3 = b
2 answers
31 - 21 = 21 people to sat on blankets.
21people * 1blanket/3people = 21 * 1/3 = 7 blankets needed.
21people * 1blanket/3people = 21 * 1/3 = 7 blankets needed.