Answer:
paper clips = $1.85
index cards = $3.95
Step-by-step explanation:
Mark
12 paper clips = x
10 index cards = y
$61.70 total
Janice
15 paper clips = x
7 index cards = y
$55.40 total
12x + 10y = 61.70
15x + 7y = 55.40
*** you want to cancel out one of the letters
(12x + 10y = 61.70) * -7
(15x + 7y = 55.40) * 10
-84x -70y = -431.9
150x + 70y = 554.0
150x + 70y = 554.0
-84x -70y = -431.9
66x + 0 = 122.1
66x = 122.1
x = 122.1 ÷ 66
x = 1.85
plug it back in
15(1.85) + 7y = 55.40
27.75 + 7y = 55.40
7y = 55.40 - 27.75
7y = 27.65
y = 27.65 ÷ 7
y = 3.95
Answer:
41
Step-by-step explanation:
x=12
so y=3⋅12 +5
=36+5
=41
Answer: Around 96 people would prefer creamy peanut butter.
Step-by-step explanation:
In the survey was found that 4 out of 5 preferred creamy over chunky peanut butter.
Then the relative frequency is:
4/5 = 0.8 prefer creamy peanut butter.
And we can assume that:
1/5 = 0.2 prefer chunky peanut butter.
We also could multiply these numbers by 100% to obtain the percentage forms:
0.8*100% = 80%
0.2*100% = 20%
Now, if there are 120 people in the grocery store, we can expect that the 80% will prefer creamy peanut butter.
Then we can expect that the number of people that prefers creamy peanut butter is:
N = (80%/100%)*120 = 0.8*120 = 96
Around 96 people would prefer creamy peanut butter.
Answer:
Step-by-step explanation:
Jack's method is equivalent because of the "law of commutative property", which means that multiplication problems have the same result no matter the order.
2x5 is the same as 5x2
Be:
Number of hours: n
<span>The cost of renting a bike for the first hour is $7:
n=1→f(n)=f(1)=$7
</span>He is charged $2.50 for every additional hour of renting the bike:
f(n)=f(n-1)+2.50, for <span>n ≥ 2
</span>
f(1)=7; f(n)=f(n-1)+2.50, for <span>n ≥ 2 (sixth option)
</span>
f(n)=f(1)+2.50(n-1)
f(n)=7+2.50(n-1)
f(n)=7+2.50n-2.50
f(n)=2.50n+4.50 (fifth option)
Answers:
Fifth option: f(n)=2.50n+4.50, and
Sixth option: f(1)=7; f(n)=f(n-1)+2.50, for <span>n ≥ 2</span>
