Question

There are 8 elephants in the zoo. Each elephant eats about 2.16 * 105 pounds of vegetation per year. The zookeeper asked Nate and Elena to determine how many pounds of vegetation is required to feed all of the elephants. They wrote their solutions in scientific notation.

Answer 1

According to the associative property of multiplication,

`a*(b* c)=(a* b)* c`

Using this property, the correct calculation is,

`8*(2.16*10^5)=(8*2.16)*10^5`

Elena's calculation given by,

`8*(2.16*10^5)=(8*2.16)*(8*10^6)`

In the above calculation, associative property of multiplication is not followed.

Also, in scientific notation, a number between 1 and 10 is multiplied by power of 10. In Elena's answer, the number 1.728 is multiplied by a power of 80. So, the answer is not in scientific notation too.

Hence, Elena's answer is wrong because she didn't follow the associative property of multiplication and the rule of scientific notation.