Answer:
x= 29/15
Step-by-step explanation:
The amount of the discount was $140.
Answer:
n=-6
Step-by-step explanation:
5n-42=12n
5n=12n+24
5n-12n=42
-7n=42
divide each side by -7
n does =-6
Answer:

Step-by-step explanation:
3 envelopes having 2 red card
2 envelopes having 1 red card and 1 black card
1 envelope having 2 black cards
We are given that . An envelope is selected at random and a card is withdrawn and found to be red.
So, No. of ways of envelope having red card = 3+2 = 5
No. of required ways of envelope having 1 red card and 1 black card = 2
So, probability of getting an envelope having 1 red card and 1 black card = 
Hence The chance the other card is black is 
1/80 = 0.0125
1/5 = 0.2
0.0125-0.2 = -0.1875
-0.1875 = -3/16