Answer:
40%
Step-by-step explanation:
(21-15)/15=0.4
0.4×100=40
SOLUTION
Given the question in the image, the following are the solution steps to answer the question.
STEP 1: State the number of outcomes possible for three tossing of a coin
Since a coin has two possible outcomes and is tossed three times, the total outcomes will be:

STEP 2: Find the number of sample spaces for the three tosses
STEP 3: Get the outcomes of the events for which the second toss is tails
Hence, the answers are given as:
Sample Space:

The event that the second toss is tails:
<em>Denote x2 by y.
</em>
<em> </em>
<em>(x2-3)7=(y-3)7
</em>
<em> </em>
<em>This is a binomial expansion in y, and you want the coefficient of y4 because y4=x8
</em>
<em> </em>
<em>You have 7 terms of (y-3) in (y-3)7. To get the fourth power of y, you need to choose y from four of the terms. The number of ways you can do this is the combinations of 7 things taken 4 at a time. This is:
</em>
<em> </em>
<em>7!/(4!3!)=35</em>
<em />
<em>So, the coefficient of x8 in the given expansion will be 210.</em>
<em>HOPE IT HELPS</em>
<em>THANK YOU </em>
Answer:
178.3 mm²
Explanation:
The surface area of the regular pyramid is equal to the sum of the base and lateral areas:()