Answer:
3 boxes
Step-by-step explanation:
First, we find how many cubes are in each box, then we find how many boxes you need for 140 cubes.
To find the number of cubes in a box we need to find the volume of the figure
the top is 2 wide and 4 long so there are 8 cubes on each layer. Sense it is 8 cubes tall with 8 cubes on each layer the model has 8×8=64 cubes in each box.
Now we divide then round up to find how many full boxes she needs to get 140 cubes or more.
If 1 box has 64 cubes and she needs 140 cubes 140/64=2.187. Now we round up sense he can't buy a fraction of a box and the answer is: She needs 3 boxes
