Final answer:
To find the number of cats Morgan saw over the two days, multiply the number she saw on Sunday by 3 and add it to the number she saw on Monday.
Step-by-step explanation:
To find the number of cats Morgan saw over the two days, we need to determine the number of cats she saw on Monday and add it to the number of cats she saw on Sunday. Since Morgan saw three times as many cats on Monday as on Sunday, we can multiply the number she saw on Sunday (3 x 10^1) by 3 to find the number of cats she saw on Monday. This gives us 3 x (3 x 10^1) = 3 x 30 = 90 cats. To find the total number of cats she saw over the two days, we simply add the number she saw on Sunday (3 x 10^1) to the number she saw on Monday (90). Therefore, Morgan saw a total of 30 + 90 = 120 cats over the two days. The correct answer is option C. 120.