Answer:
The probability is 169/2652
Step-by-step explanation:
The number of cards in a deck of cards is 52
In each deck of cards, there are 13 black cards and 13 spade cards
The probability of selecting a spade card will be;
13/52 = 1/4
Without replacement, we are left with 51 cards and the probability of selecting a black card will now be 13/51
So the probability of the second card being a black card if the first is spade will be ;
13/52 * 13/51
= 169/2,652
This is a sum and difference problem, with the equations
R-N=35
R+N=635
The solution of which is
R=(635+35)/2=335
N=(635-35)/2=300
In general, the sum and difference problem can be solved (most of the time mentally) using
Larger number = (sum + difference)/2
Smaller number = (sum - difference)/2
Answer:7/8
Step-by-step explanation:
It is 7/8 because it is the fraction that is closest to a whole number