Question

Kerrie uses the work shown below to determine 35% of 280.

Step 1: 35% = 10% + 25%

Step 2: 10% of 280 = 280:10 = 28

Step 3: 25% of 280 = 280 : 4 = 70

Step 4: 28 + 70 = 98

She states that 35% of 280 is 98. Which is a true statement about Kerrie's solution?

Kerrie's solution is correct.

Kerrie incorrectly determined 10% in Step 2.

Kerrie incorrectly determined 25% in Step 3.

Kerrie incorrectly combined the solutions from Step 2 and Step 3 in Step 4.

Answer 1

Kerrie's solution is correct.

Explanation:

Each step of Kerrie's solution is correct, because 10% + 25% is actually 35%. Also, 10% of 280 is 28, because we divide 280 by 10. The third step is also correct because 25% is the same as the fourth part, or divide by four, because 25% is the fourth part of 100%.

At last, the sum 70 + 28 is also correct, because it results in 98.

Basically, Kerrie made a different process, but it gives the same result. Because we only could do it like this:

`(35\%)/(100\%)=0.35`

Then,
`280(0.35)= 98`

As you can see, it results the same number.

Answer 2

For this case we must find 35% of 280.

Kerrie gets 10% and then 25%. So:

10% of 280:

280 ------------> 100%

x -----------------> 10%

Where "x" represents the amount given by 10% of 280.

`x = \frac {10 * 280} {100}\\x = 28`

Thus, 10% of 280 is 28.

Now, we find 25% of 280:

280 ------------> 100%

x -----------------> 25%

Where "x" represents the amount given by 25% of 280.

`x = \frac {25 * 280} {100}\\x = 70`

Thus, 25% of 280 is 70.

So we have that 35% of 280 is given by:

`28 + 70 = 98`

So, Kerrie's solution is correct.

Answer:

Option A