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 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 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 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.
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 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 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 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.
Answers
GPT-4o mini
The mistake that Sammy made was:
**Sammy needed to convert 10 ft. to 120 in. by multiplying by 12 in.1 ft. before substituting.**
To calculate the time correctly using the formula \( t = \frac{d}{r} \), Sammy should have first converted the distance from feet to inches, since the speed is given in inches per second.
10 feet is equal to 120 inches (since \(10 \text{ ft} \times 12 \text{ in/ft} = 120 \text{ in}\)). Once that conversion is made, he can then use the formula correctly with the distance in inches and the speed in inches per second.
**Sammy needed to convert 10 ft. to 120 in. by multiplying by 12 in.1 ft. before substituting.**
To calculate the time correctly using the formula \( t = \frac{d}{r} \), Sammy should have first converted the distance from feet to inches, since the speed is given in inches per second.
10 feet is equal to 120 inches (since \(10 \text{ ft} \times 12 \text{ in/ft} = 120 \text{ in}\)). Once that conversion is made, he can then use the formula correctly with the distance in inches and the speed in inches per second.