So chance to get a black pen: 4/10=2/5
Chance to get a red pen: 1/10
Chance for the two happened at the same time
2/5 * 1/10 = 2/50=1/25
I think... I’m not very sure though
Once your friend has thought of a number, do the following:
1. Ask him or her to multiply the chosen number by 2.
2.Choose an even number to use yourself. Ask your friend to add this number to the one in his head.
3.Tell him/her to divide the new number by 2.
4.Tell your friend to subtract his original number from the equation.
5."Guess" the number.
:)
Answer:
x = 2n - 4
Step-by-step explanation:
hope this helped have a great day
You can use lattice multiplication or long multiplication. for examples and/or visuals message me.