12 x 12 = 144
11 x 11 = 121
Sqrt130 between the two,
Based on the given parameters of a = 1.7 cubic feet and concrete for first 4 steps as 17 cubic feet, the concrete is required for the first 12 steps is 132.6 cubic feet
<h3>Arithmetic progression</h3>
- First term, a = 1.7 cubic feet
- Sum of first four terms = 17 cubic feet
Sn = n/2 {2a + (n - 1) d}
17 = 4/2{2×1.7 + (4 - 1)d}
17 = 2{3.4 + (3)d}
17 = 2(3.4 + 3d)
17 = 6.8 + 6d
17 - 6.8 = 6d
10.2 = 6d
d = 10.2/6
- Common difference, d = 1.7
Concrete required for first 12 steps;
Sn = n/2 {2a + (n - 1) d}
= 12/2{2×1.7 + (12-1)1.7}
= 6{3.4 + (11) 1.7}
= 6(3.4 + 18.7)
= 6(22.1)
= 132.6
Concrete required for first 12 steps = 132.6 cubic feet
Learn more about sum of arithmetic progression:
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Answer:
It's 152 r10
Step-by-step explanation:
152 x 42 = 6,384
6,384 + 10 = 6,394
Answer:
5.78% probability that exactly 2 of them use their smartphones in meetings or classes.
Step-by-step explanation:
For each adult, there are only two possible outcomes. Either they use their smarthphone in meetings or classes, or they do not. The probability of an adult using their smartphone on meetings or classes is independent of other adults. So we use the binomial probability distribution to solve this question.
Binomial probability distribution
The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.
In which is the number of different combinations of x objects from a set of n elements, given by the following formula.
And p is the probability of X happening.
63% use them in meetings or classes.
This means that
7 adult smartphone users are randomly selected
This means that
Find the probability that exactly 2 of them use their smartphones in meetings or classes.
This is P(X = 2).
5.78% probability that exactly 2 of them use their smartphones in meetings or classes.