The explicit formula for arithmetic sequence is:
an=a+(n-1)d
where:
a=first term
d=common difference
given:
a3=22
a(17)=-20
substituting this in our equation we get:
22=a+(3-1)d
22=a+2d
a=22-2d........i
also:
-20=a+(17-1)d
-20=a+16d.....ii
but substituting i in ii we get:
-20=22-2d+16d
-20-22=14d
-42=14d
d=-3
but:
a=22-2d
a=22-2(-3)
a=28
thus the formula will be:
an=28-3(n-1)
thus the first term will be 28
the 2nd term will be:
a2=28-3(2-1)
a2=25
the 3rd term will be:
a3=28-3(3-1)
a3=28-6
a3=22
a4=28-3(4-1)
a4=28-9
a4=15
a5=28-3(5-1)
a5=28-3(4)
a5=28-12
a5=15
Answer:
5/16
Step-by-step explanation:
As you can see in the 16 given possible outcomes, in 5 of them at least 3 coins land facing up. Since there are 16 outcomes in total, the probability that at least three coins land facing up is 5/16. Hope this helps!
70 pieces
7/10 = x/100
10*10=100
7*10 = 70
70/100
Complete question :
The latter is leaning against the building so that the distance from the ground to the top of the ladder is 9 feet less than the length of the ladder finally put the ladder in the distance from the bottom of the ladder to the building 15 feet. Find length of the ladder.
Answer:
17
Step-by-step explanation:
From Pythagoras :
Hypotenus = sqrt(opposite² + adjacent²)
From the diagram
l = sqrt((l-9)² + 15²)
l² = (l² - 18x + 81 + 225)
Square both sides
l² = l² - 18x + 306
l² - l² = 306 - 18x
18l = 306
l = 306/18
l = 17
