Answer:
The value of A is 5
Step-by-step explanation:
- The number is divisible by 3 if the sum of its digits is a number
divisible by 3
- Ex: 126 is divisible by 3 because the sum of its digits = 1 + 2 + 3 = 6
and 6 is divisible by 3
- The number is divisible by 5 if its ones digit is zero or 5
- Ex: 675 is divisible by 5 because its ones digit is 5
890 is divisible by 5 because its ones digit is 0
- We are looking for the value of A in the 4-digit number 3A5A which
makes the number divisible by both 3 and 5
∵ A is in the ones position
∴ A must be zero or 5
- Let us try A = 0
∵ A = 0
∴ The number is 3050
∵ The sum of the digits of the number = 3 + 0 + 5 + 0 = 8
∵ 8 is not divisible by 3
∴ 3050 is not divisible by both 3 and 5
∴ A can not be zero
- Let us try A = 5
∵ A = 5
∴ The number is 3555
∵ The sum of the digits of the number = 3 + 5 + 5 + 5 = 18
∵ 18 is divisible by 3
∴ 3555 is divisible by both 3 and 5
∴ A must be equal 5
* <em>The value of A is 5</em>
Answer:
4
Step-by-step explanation:
St meaans s times t
s=-4
t=9
st=-4 times 9
negative times positive=negative
4 times 9=36
-4 time s9=-36
st=-36
answer is -36
The number of 10 chips stacks that Dave can make if two stacks are not considered distinct is 110.
The solution
To get the symmetric stacks, one has to subtract the symmetric stacks to know the ones that are asymmetric.
The symmetric are flipped. Given that they are double counted what we have to do is to divide through by 2.
6/2 = 3
10/2 = 5
4/2 = 2
1/2(10C6) - (5C3) + (5C3)
0.5(210-10+10)
= 110
