Question

Raul is building a house

On day 1, he uses 3 bags of cement
On each of the following 3 days, he uses 3 times the number of bags used the previous day
How many bags of cement does he use in the last 3 days?

Answer 1

117 bags

Explanation:

First day number of bags used by Raul= 3 bags

We have to calculate the number of bags next three following days

On second day, number of bags used by Raul= 3×3=9

similarly, on third day number of bags used by Raul= 9×3=27

similarly, on fourth day number of bags used by Raul= 27×3=81

Hence, the total number of bags used by Raul= 9+27+81=117

Hence, the correct answer is 117

Answer 2

The given situation above is an example of a geometric sequence with first term equal to three and the common ratio equal to 3. For the second day, Raul used 9 bags of cement. He used 27 bags on the third and 81 on the fourth. To answer the question, add the number of bags from second to fourth day. The answer is equal to 117 bags of cement.