The amount invested is $ 470
<h3><u>Solution:</u></h3>
Given that , we have earned $131.60 as simple interest for an amount deposit at the rate of 4% for seven years.
We have to find the amount invested. That is, we need to find the principal sum
Let us use the simple interest formula
<em><u>The simple interest is given as:</u></em>

Here, simple interest = $ 131.60
Rate of interest = 4 %
Number of years = 7
principal = ?
Substituting the values in formula, we get

Thus the amount invested is $ 470
9/8 because you multiply 3 × 3 and leave the denominator the same
<span>Defective rate can be expected
to keep an eye on a Poisson distribution. Mean is equal to 800(0.02) = 16,
Variance is 16, and so standard deviation is 4.
X = 800(0.04) = 32, Using normal approximation of the Poisson distribution Z1 =
(32-16)/4 = 4.
P(greater than 4%) = P(Z>4) = 1 – 0.999968 = 0.000032, which implies that
having such a defective rate is extremely unlikely.</span>
<span>If the defective rate in the
random sample is 4 percent then it is very likely that the assembly line
produces more than 2% defective rate now.</span>