Answer:
$80
Step-by-step explanation:
From the question, we are given The simple interest formula as I = Prt,
where l = simple interest on an amount= $40
t= years=5years
at a rate r= 10%
The rate= 10/100= 0.1
Then since we are looking for P, we can make P subject of formula from this expression;
I = Prt
P=I/rt
P= 40/(0.1 ×5)
P= 40/0.5
P= 80
therefore, the amount of money p that is needed is $80
Answer:

Step-by-step explanation:
In order to find r we have to square both sides of the equation

The *square root* sign cancels out the *squared* sign therefore:

Answer:
65
Step-by-step explanation:
Answer:
x = 2 or x = -2
Step-by-step explanation:
5x² - 15 = 5
⇌
5x² = 15 + 5
⇌
5x² = 20
⇌
x² = 20/5 = 4
⇌
x² = 2²
⇌
x² - 2² = 0
⇌
(x - 2)(x + 2) = 0
⇌ we use the zero product property
x - 2 = 0 or x + 2 = 0
⇌
x = 2 or x = -2
Answer:
Karen: 15; Dale: 9; Tom: 60
Step-by-step explanation:
"Karen and Dale and Tom sent a total of 84 messages during the weekend."
k + d + t = 84
"Dale sent six fewer messages than Karen"
d = k - 6
"Tom sent four times as many as Karen."
t = 4k
Substitute k - 6 for d and 4k for t in the first equation.
k + d + t = 84
k + k - 6 + 4k = 84
6k - 6 = 84
6k = 90
k = 15
d = k - 6 = 16 - 6 = 9
t = 4k = 4(15) = 60
Answer: Karen: 15; Dale: 9; Tom: 60