Answer: 3x3=9, 4x5=20, 8x9=72, and 7x3=21!
Step-by-step explanation:
Let x be ml of 5% soln.
let 500-x be ml of 25% soln.
.
x*.05=.05x
(500-x)*.25=125-.25x
500*.20=100
.
.05x+125-.25x=100
-.2x=-25
x=-25/-.2
x=125 ml of 5% soln.
500-x=375 ml of 25% soln.
.
Check:
125*.05= 6.25
375*.25=93.75
---------------
========100
A. X ~ N(66, 6.25)
b.
Using a standard normal probability table to find probability values for the z-scores, we get:
P(65 < X < 69) = 0.1554 + 0.3849 = 0.5403
c. z= 0.524 and -0.524
1.31 = X - 66
X = 67.31
When z = -0.524, X = 64.69.
P(64.69 < X < 67.31) = 0.4
Answer: it will take 13.3 years
Step-by-step explanation:
We would apply the formula for determining compound interest which is expressed as
A = P(1+r/n)^nt
Where
A = total amount in the account at the end of t years
r represents the interest rate.
n represents the periodic interval at which it was compounded.
P represents the principal or initial amount deposited
From the information given,
P = 6000
A = 10000
r = 4% = 4/100 = 0.04
n = 12 because it was compounded 12 times in a year.
Therefore,.
10000 = 6000(1 + 0.04/12)^12 × t
10000/6000(1 + 0.0033)^12t
1.67 = 1.0033^12t
Taking log to base 10 of both sides, it becomes
Log 1.67 = 12tLog 1.0033
0.223 = 12t × 0.0014
0.223 = 0.0168t
t = 0.223/0.0168
t = 13.3 years
