Step-by-step explanation:
Right, okay, so this is a bit of a weird one. Let's go step by step.
"Today, 6 friends went out for lunch." = The number 6 is gonna be in our equation somewhere.
"Their total bill was $27.60" = so is the number 27.6
"They decided to split the bill equally" = 27.6 "split equally" (aka divided by) 6 friends is 4.6
"each paid with a $10 bill" = This is where it gets a lil weird. So, if they divided the bill among them, none of their amounts are gonna be anywhere near ten dollars. This is one of those questions that wouldn't really happen in real life. People would probably use fives instead, but whatever. So a number we'll be using for something is 10.
"How much money will each person get back?" = So we have to find the amount they all paid (10) minus the amount each one had to pay (4.6).
To put it all into a full equation...
10 - ( 27.6 / 6 )
Divide.
10 - 4.6
Subtract.
5.4
Put back into money form.
$5.40
Answer:
Each person will get back $5.40.
Haileys work is correct so B should be the right answer
Answer: Exponential decay model:
y
=
x
(
1
−
r
)
t
, half life of tablet is about
2
hours and after
t
=
3
hours , remaining drug on patient's system is
42.875
mg.
Step-by-step explanation: Initial drug
x
=
125
mg ; rate of decay
r
=
30
100
=
0.3
gm/hour
Exponential model:
y
=
x
(
1
−
r
)
t
=
125
(
1
−
0.3
)
t
=
125
⋅
0.7
t
Half life:
y
=
125
2
=
62.5
mg
∴
62.5
=
125
⋅
0.7
t
or
0.7
t
=
1
2
. Taking logarithm on both sides we get ,
t
log
(
0.7
)
=
log
(
0.5
)
∴
t
=
log
(
0.5
)
log
(
0.7
)
≈
1.94
(
2
d
p
)
hour
The half life of tablet is about
2
hours.
After
t
=
3
hours , remaining drug on patient's system is
y
=
125
⋅
0.7
t
=
125
⋅
0.7
3
=
42.875
mg [Ans]
The last option is the answer. You can double check by substituting the -3 for the x values and the 17 for y values and the statements would be true.
