26 black cards plus 12 face cards = 38 out of 52. About a 73% chance.
Answer:
13,000 ft.
Step-by-step explanation:
X -------10960----------C---------------D---------------Y
The entire race (from X to Y) is 7 miles. There are 5,280 ft. in one mile, so 7 miles is 36960 ft.
If we subtract 10,960 from 36,960, then we get the distance from C to Y.
36960-10960 = 26000
They tell you D is at the midpoint between C and Y
So if we divide 26,000 by 2, then we know the distance from C to D and from D to Y.
26000/2 = 13000
The checkpoints are C and D, so the distance between them is 13,000 ft.
ANSWER

EXPLANATION
The exponential function that models cell duplication in the lab is given as

We want to determine the time it will take for the cells to increase to

In other words, we want to find the value of

when

This gives us the equation,

Recall that,

We apply this property to the right hand side to obtain,

This implies that,

We divide both sides by 4 to get,

We take the antilogarithm of both sides to base 10 to get,

This implies that,

to the nearest hundredth.
keeping in mind that there 60 seconds in 1 minute, and about 1.609 kilometers in 1 mile.

6/30 and 3/15 would both work.