Answer:
1/4
Step-by-step explanation:
Let's denote the probabilities as following:
Probability that a teenager has a sister:
P(A) = 12/28
Probability that a teenager has a brother:
P(B) = 7/28
Probability that a teenager has both a sister and a brother:
P(A⋂B) = 3/28
Probability that a selected teenager has a sister also has a brother, or in other words, he/she has a brother, given he/she had a sister:
P(B|A)
Let's apply the formula of conditional probability to work out P(B|A)
P(B|A) = P(A⋂B)/P(A) = (3/28)/(12/28) = (3*28)/(12*28) = 3/12 = 1/4
=> Option C is correct
Hope this helps!
Answer:
There are 585 adults and children
Step-by-step explanation:
Let the number of adults be a, number of children be c and the number of seniors be a
Amount made per group;
adults; 52 * a = 52a
Children : 26 * c = 26c
Seniors = 20 * s = 20s
Adding all will give 20,490
52a + 20s + 26c = 20 490 ••••(i)
Now let us work with the ratios;
a : s = 6 : 1
a/s = 6/1
a = 6s •••••(ii)
Lastly;
a/c = 4/9
4c = 9a ••••(ii)
We want to get a + c
From the first equation , let’s substitute
52(6s) + 20s + 26c = 20,490
26c = 6.5 (4c)
but 4c = 9a; 6.5(9a)
But a = 6s
So we have; 6.5(9)(6s) = 351s
so we have;
312s + 351s + 20s = 20,490
683s = 20,490
s = 20490/683
s = 30
Recall;
a = 6s = 6 * 30 = 180
4c = 9a
4c = 9 * 180
c = (9 * 180)/4 = 405
So the total number of children and adult is a + c
405 + 180 = 585
Answer:
320
Step-by-step explanation:
17 pieces. She had two and she had to have 15 to give to the children. If each child got 3 and there is 5. This turns into 3*5=15. Then you would add 15+2 to get 17
