Answer:
21
ctto JBarnum
Step-by-step explanation:
P+11=(1/2)(P-13)^2
P+11=(1/2)(P^2-26p+169)
2(P+11)=(1/2)(2)(P^2-26p+169)
2P+22=P^2-26p+169
0=P^2-28p+147 ( -7 and -21)
(P-7)(P-21)=0
P=7,21 (cant be 7 as 13 years from 7 is negative so peter is 21)
checking:
21+11=32
32=(1/2)(21-13)^2
32=(1/2)(8)^2
32=(1/2)64
32=32
correct
Answer:
Student B is correct
Student A failed to distribute -4 and -6 when opening the brackets in the first step
Step-by-step explanation:
The solution Student A gave was:
2x - 4(3x + 6) = -6(2x + 1) - 4
2x - 12x + 6 = -12x + 1 - 4
-10x + 6 = -12x - 3
2x = -9
x = -4 _1 2 ( -4 1/2)
The solution Student B gave was:
2x - 4(3x + 6) = -6(2x + 1) - 4
2x - 12x - 24 = -12x - 6 - 4
-10x - 24 = -12x - 10
2x = 14
x = 7
Student B is correct.
Explanation of the error:
Student A failed to distribute -4 and -6 when opening the brackets in the first step.
That is,
2x - 4(3x + 6) = -6(2x + 1) - 4
To open this bracket, we will distribute, -4 and -6 so that we get
2x (-4 × 3x) + (-4 × +6) = (-6×2x) + (-6 × +1) - 4
Then we will get
2x -12x -24 = -12x -6 -4
Adding the like terms
-10x - 24 = -12x - 10
Collecting like terms
-10x + 12x = -10 + 24
∴ 2x = 14
x = 14 / 2
Hence,
x = 7
Answer:
Principal: $6,166.67
Principal: $5,200.00
Explanation:
<u><em>1. $6000 for 50 days at 20% p.a</em></u>
<u><em></em></u>
In 20% pa, pa means "per annum", i.e. "per year".
Assume simple interest:
Interest:
- Interest = Principal × number of days × annual rate / 360
- Interest = $6,000 × 50 × 20% / 360 = $166.67
Principal = principal + interest = $6,000 + $166.67 = $6,166.67
<u><em></em></u>
<u><em>2. $5000 for 5 months at 0.8% per month</em></u>
Assume, again, simple interest.
- interest: 0.80% per month
Interest:
- Interest = Principal × number of months × montly rate
- Interest = $5,000 × 5 × 0.80% = $200.00
Principal = principal + interest = $5,000 + $200.00 = $5,200
You can see that the accrued interests depend on the principal, the interest rate, and the time.
Answer:
Step-by-step explanation:
(2n - 3)(5n + 6) = 2n*(5n + 6) -3*(5n +6)
=2n*5n + 2n*6 -3*5n + (-3)*6
=10n² + 12n - 15n - 18
= 10n² -3n - 18
Answer:
x = 3
Step-by-step explanation:
we can use the Pythagorean theorem to solve this problem
x^2 + 4^2 = 5^2
x^2 + 16 = 25
x^2 = 9
x = +/- 3
we take only the positive value because a length can‘t be negative
x = 3
