Sandi tracks her calories burned during water aerobics class. The number of calories she burns is expressed by the function c(t) = 350t, where t is the number of hours spent doing water aerobics.

To burn more calories, Sandi wears ankle weights during her class. The number of calories she burns while wearing ankle weights is expressed by the function b(c) = 1.2c, where c is the number of calories burned doing water aerobics without weights.

Which of the following composite functions expresses the calories, as a function of time, Sandi burns while doing water aerobics with ankle weights?

Question

Sandi tracks her calories burned during water aerobics class. The number of calories she burns is expressed by the function c(t) = 350t, where t is the number of hours spent doing water aerobics.

To burn more calories, Sandi wears ankle weights during her class. The number of calories she burns while wearing ankle weights is expressed by the function b(c) = 1.2c, where c is the number of calories burned doing water aerobics without weights.

Which of the following composite functions expresses the calories, as a function of time, Sandi burns while doing water aerobics with ankle weights?

egracer · Answer

the options are 

 b[c(t)] = 351.2t
 b[c(t)] = 420t
 c[b(t)] = 351.2t
 c[b(t)] = 420t

egracer · Answer

Open study kind of sucks nobody ever helps me..

egracer · Answer

Is it C????? thats what i got through by calculations

egracer · Answer

@ganeshie8 @Hero @phi

vocaloid · Answer

first find b(t)

if b(c) = 1.2c, then what is b(t)?

egracer · Answer

b(t)=351.2 @Vocaloid

vocaloid · Answer

uh, not quite

all we're doing is replacing "c" with "t"

so, if b(c) is 1.2c, then what is b(t)?

vocaloid · Answer

hint: all you need to do is replace "c" with "t"

egracer · Answer

1.2t??

vocaloid · Answer

right

now, we have b(t) = 1.2t
now we need to find c(b(t))

if c(t) = 350t, then what is c(b(t))?

hint: replace "t" with "1.2t"

egracer · Answer

350c(1.2t)

egracer · Answer

im not really sure  I'm a little confused

vocaloid · Answer

c(t) = 350t
c(b(t)) = c(1.2t) = ?

egracer · Answer

350(1.2)?

vocaloid · Answer

almost...

if c(t) is 350 times t, then c(1.2t) is 350 times ____ 

fill in the blank

egracer · Answer

that is so confusing could you break it down some more its really confusign me

vocaloid · Answer

c(t) = 350*t
c(1.2t) = 350*___

fill in the blank

egracer · Answer

350 times 1.2 thats all i can think of

vocaloid · Answer

almost, you're missing something important

egracer · Answer

the t?

vocaloid · Answer

yes!

egracer · Answer

so its 350*1.2t

vocaloid · Answer

yeah, and what do you get when you multiply?

egracer · Answer

420t

egracer · Answer

so would it be D?

vocaloid · Answer

ah, it should be B, my mistake

b(c(t)) = 420t

egracer · Answer

thank you so much

egracer · Answer

EVERYONE B WAS CORRECT.