Quandaries and Queries
Who is asking: Parent
My son came home with a question and asked me to help him with it. As I strugged through it I came up with an answer of 27. However I'm not sure how to explain it to him. Maybe you can help.
Red riding hood had a number of jars to take to grandma's house. As she traveled she gave away 1/3 of them to an old lady. Then later As she walked through the forest a wolf stole 1/2 of her remaining jars. When she arrived at grandma's house she gave her 2/3 of the remaining jars. She kept 6 jars for herself. How many jars did she start out with.
This is an interesting problem to solve because it requires students to work backwards and working backwards is one problem solving strategy that students learn in school.
So, working backwards, she is left with 6 jars, which is 1/3 of what she had before she gave grandma 2/3 of the jars. So that she had 18 jars when she arrived at grandma's.
Before that she ran into the wolf who stole 1/2 of what she had. Since she had 18 left after he stole half, she had 36 before she ran into the wolf. Before running into the wolf, she gave away 1/3 to an old lady, so that what she had left was 2/3 and that was 36. And 3/3 would be 54 jars.
It also helps if you make a timeline as you work backwards through the problem.
If you liked that one, here's another similar one:
The Christmas Oranges
Freddie received a box of Christmas oranges from a newspaper customer. By the time he had finished his paper route, Freddie had eaten 1/3 of the oranges.
When he arrived home, Freddie hid the box from his little brother. Returning later for the box, Freddie discovered 3⁄4 of the hidden oranges missing and only six oranges were left.
How many oranges were in the box when Freddie received the gift from his customer?
Show your work and explain how you solved the problem.