10
Step-by-step explanation:
x + 5 = 2x - 5
x + 5 <u>- x </u>= 2x - 5 <u>- </u><u>x</u>
5 = x - 5
5 + 5 = x
<u>10 = x</u>
If the speed of the stream is x
Time is given by d/r , where r is the rate and d is the distance;
Rate for upstream = (15-x) mph and that of down stream is (15 +x) mph
The time taken will be the same;
Thus; 2/(15-x) = 4/(15+x)
cross multiplying;
30 +2x = 60 -4x
6x = 30
x =5
Therefore the rate of the river is 5 mph
Answer:
B. x ≤ 2.
Step-by-step explanation:
56 - 10x ≥ 20 + 8x
-18x ≥ -36
x ≤ -36/-18 = 2. ( Note that the inequality sign flips because we are dividing by a negative value).
Assuming that each marble can be picked with equal probability, we notice that there is a total of
marbles, of which 2 are red.
So, the probability of picking a red marble is
In fact, as in any other case of (finite) equidistribution, we used the formula
