Final answer:
To determine Peter's number, we set up the equation (n – 13) × -7 = -70 where n represents Peter's number. Simplifying the equation by dividing by -7 and then adding 13 to both sides gives us Peter's number as 23.
Step-by-step explanation:
To find Peter’s number based on the condition he describes, we need to set up an equation and solve for his number. Peter says, “If you subtract 13 from my number and multiply the difference by -7, the result is -70.”
Let's denote Peter's number as n. According to his statement, the equation would be:
(n – 13) × -7 = -70
Divide both sides by -7 to isolate the difference on one side:
n – 13 = -70 / -7
n – 13 = 10
Add 13 to both sides to find n:
n = 10 + 13
n = 23
Therefore, Peter's number is 23.