Question

and "t=?" what?

Answer 1

@aichelle_02 Hi,

\(\huge \color{red}{\text{Welcome to Open Study}}\ddot\smile\)

Can you please post the entire question, so that we can help you.

Answer 2

A laboratory has 20 grams of a radioactive substance that decays in such a way that t days later the number of grams left will be y = 20(1/10)t/15 . How much will be present after 10 days?
if y is equivalent to 10; so.. 10=20(1/10)t/15, then t is equivalent to?

Answer 3

y = amount left after t days , so y is NOT equivalent to 10
t=10
put t=10 in y = 20(1/10)t/15 .
and find y to get the amount present after 10 days.
did u get this?

Answer 4

y=20(1/10)10/15
y=20(0.1)0.6
y=20(0.06)
y=1.2

is that correct?

Answer 5

how did you know that t is equal to 10?

Answer 6

sorry for late reply
t is the number of days, and given is 10 'days'
so t=10

Answer 7

and to be accurate, 10/15*0.1= 0.0666
so 20*0.0666=1.3333=y

Answer 8

I SEE

Answer 9

so 1.333 grams.

Answer 10

BUT THE CHOICES ARE A. 0 g B. 4.31 g C. 7.85 g D. 11.3 g