Let's carefully review Mariah's work:
Mariah is trying to determine how many times the spinner will land on a number greater than 7 in 250 spins. She uses the formula:
[tex]\[ P(\text{number greater than 7}) = \frac{\text{Numbers greater than 7}}{\text{Total number of sections}} \cdot \text{Number of spins} \][/tex]
First, let's identify the numbers greater than 7. The spinner has the numbers 1 through 10. The numbers greater than 7 are:
[tex]\[ 8, 9, 10 \][/tex]
There are 3 numbers greater than 7.
Next, the total number of sections on the spinner is 10.
So the correct calculation should be:
[tex]\[ P(\text{number greater than 7}) = \frac{3}{10} \cdot 250 \][/tex]
Let us calculate this step-by-step:
1. Calculate the probability of landing on a number greater than 7 in one spin:
[tex]\[
\frac{\text{Numbers greater than 7}}{\text{Total number of sections}} = \frac{3}{10}
\][/tex]
2. Multiply this probability by the total number of spins:
[tex]\[
\frac{3}{10} \cdot 250 = 75
\][/tex]
So, Mariah should have used the correct numerator, which is 3, because there are 3 numbers greater than 7 (8, 9, and 10). The correct answer to the number of times the spinner will land on a number greater than 7 in 250 spins is 75.
The mistake Mariah made was that she used 4 instead of 3 as the number of numbers greater than 7. Therefore, the correct option is:
Mariah should have used a 3 in the numerator because there are 3 numbers greater than 7.
