3rd grade Math
posted by Dominique on .
In Harry's attic there are 3 spider webs. The first web is twice as large as the second. The 3rd web is 3 inches larger than the 1st web. The combined width of the 3 webs is 1 foot and 6 inches. How long is each web?
Please provide explanation along with answer. Thank you in advance.
The original data is given in terms of area, but the width is not in the same units.
If area 1 = x, then area 2 = 2x and area 3 = x + 3.
If the total area = 18 square inches, then
x + 2x + x + 2 = 18
Then you can solve for x.
4x + 2 = 18
4x = 16
x = 4
I'll answer since this is unanswered, but, I don't think this is how a third grade student is expected to do this problem.
w = width of web
w = size in inches of the 2nd web
2w = size in inches of the 1st web
2w + 3 = size in inches of the 3rd web
1'6" = 18 inches
w + 2w + (2w + 3 ) = 18
5w + 3 = 18
5w = 15
w = 3
1st web = 3 inches
2nd web = 6 inches
3rd web = 9 inches
Total combined width = 18 inches
I would be very interested to learn how a grade 3 teacher would handle this type of question without relying on algebraic methods such as shown above by
PsyDAG and helper.
This sure looks like some fancy advanced grade 3 stuff.
what is symmetry