N = nickels and q = quarters
0.05n + 0.25q = 1.90
n = 2q + 3
0.05(2q + 3) + 0.25q = 1.90
0.10q + 0.15 + 0.25q = 1.90
0.10q + 0.25q = 1.90 - 0.15
0.35q = 1.75
q = 1.75/0.35
q = 5 ......there are 5 quarters
n = 2q + 3
n = 2(5) + 3
n = 10 + 3
n = 13 <=== there are 13 nickels
Answer: 3/8
Step-by-step explanation:
Since it is a fair coin, then generally, P(Head) = P(Tail) = ½
And since we've been asked to find the probability that the number of heads in the first two tosses be equal to the number of heads in the second two tosses, tossing a fair coin four times, the possible outcomes of having equal number of heads in first two tosses and second two tosses becomes:
[HHHH] or [HTHT] or [THTH] or [TTTT] or [HTTH] or [THHT]
=[½*½×½*½] + [½*½×½*½] + [½*½×½*½] + [½*½×½*½] + [½*½×½*½] + [½*½×½*½]
=1/16 * 6
=6/16
=3/8.
Answer:
a) The probability is 1/5
bi) The probability each ball is even will be 2/5
bii) The probability the sum of the numbers on the ball is not more than 10 is 16/25
(that's what I think it is)
Let the boat speed in still water be b.
Let the current speed be c.
The speed going upstream is 20/4 = 5 mph.
The speed going downstream is 32/4 = 8 mph.
b - c = 5 ........(1)
b + c = 8 .......(2)
Adding equations (1) and (2) we get:
2b = 13
b = 13/2 = 6.5
Plugging in the value for b into equation (1) we find c = 1.5.
The boat speed in still water is 6.5 mph and the current speed is 1.5 mph.
