Question
Sammy wants to calculate the time it takes for a ladybug traveling at a speed of 3 inches (in.) per second (sec.) to crawl a distance of 10 feet (ft.).
Starting with the formula d=rt, Sammy rearranges the formula to highlight time, t, as the quantity of interest.
t=dr
Sammy substitutes the values for rate and time into the formula t=dr and simplifies to calculate the time.
t=10 ft.3in.sec.t≈3.3 sec.
Sammy determines it takes the ladybug about 3.3 sec. to travel 10 ft.
What mistake did Sammy make?
(1 point)
Responses
Sammy needed to convert 3 in. per sec. to in. per minute (min.) by multiplying by 1 min.60 sec. before substituting.
Sammy needed to convert 3 in. per sec. to in. per minute (min.) by multiplying by start fraction 1 minute over 60 seconds end fraction before substituting.
Sammy did not isolate t properly. He should have used t=rd.
Sammy did not isolate t properly. He should have used t is equal to r over d .
Sammy needed to convert 10 ft. to 120 in. by multiplying by 12 in.1 ft. before substituting.
Sammy needed to convert 10 ft. to 120 in. by multiplying by Start Fraction 12 inches over 1 foot End Fraction before substituting.
Sammy needed to convert 3 in. per sec. to 36 in. per sec. by multiplying by 12 in.1 ft. before substituting.
Sammy needed to convert 3 in. per sec. to 36 in. per sec. by multiplying by start fraction 12 inches over 1 foot end fraction before substituting.
Starting with the formula d=rt, Sammy rearranges the formula to highlight time, t, as the quantity of interest.
t=dr
Sammy substitutes the values for rate and time into the formula t=dr and simplifies to calculate the time.
t=10 ft.3in.sec.t≈3.3 sec.
Sammy determines it takes the ladybug about 3.3 sec. to travel 10 ft.
What mistake did Sammy make?
(1 point)
Responses
Sammy needed to convert 3 in. per sec. to in. per minute (min.) by multiplying by 1 min.60 sec. before substituting.
Sammy needed to convert 3 in. per sec. to in. per minute (min.) by multiplying by start fraction 1 minute over 60 seconds end fraction before substituting.
Sammy did not isolate t properly. He should have used t=rd.
Sammy did not isolate t properly. He should have used t is equal to r over d .
Sammy needed to convert 10 ft. to 120 in. by multiplying by 12 in.1 ft. before substituting.
Sammy needed to convert 10 ft. to 120 in. by multiplying by Start Fraction 12 inches over 1 foot End Fraction before substituting.
Sammy needed to convert 3 in. per sec. to 36 in. per sec. by multiplying by 12 in.1 ft. before substituting.
Sammy needed to convert 3 in. per sec. to 36 in. per sec. by multiplying by start fraction 12 inches over 1 foot end fraction before substituting.
Answers
GPT-4o mini
Sammy made the mistake of not converting the distance from feet to inches before calculating the time. To properly use the formula \( d = rt \), both distance and rate need to be in the same units.
10 feet should be converted to inches:
\[
10 \text{ ft} \times \frac{12 \text{ in}}{1 \text{ ft}} = 120 \text{ in}
\]
Therefore, the correct response is:
**Sammy needed to convert 10 ft. to 120 in. by multiplying by \( \frac{12 \text{ inches}}{1 \text{ foot}} \) before substituting.**
10 feet should be converted to inches:
\[
10 \text{ ft} \times \frac{12 \text{ in}}{1 \text{ ft}} = 120 \text{ in}
\]
Therefore, the correct response is:
**Sammy needed to convert 10 ft. to 120 in. by multiplying by \( \frac{12 \text{ inches}}{1 \text{ foot}} \) before substituting.**