Question

a 15 foot building casts a 9 foot shadow. How tall is the building that casts a 30 ft shadow at the same time

Answer 1

9 + 9 = 18 + 9 = 27. 1/3 of 9 is 3 27 + 3 = 30
15 x 3 = 45. 1/3 of 15 is 5. So, 45 + 5 = 50.
The building is 50 feet tall.
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