Solve the following problems.

Question

Solve the following problems.

1. Janna has a collection of four cards numbered 1 to 4. He pairs them up so that each pair will form a two digit prime number. What is the difference between two prime numbers formed?

2. Find the sum of the least and greatest even numbers between 100 and 200?

3. Find a pair factors of 72 whose sum is 22.

4. Find a pair factors of 48 whose quotient us 12.

5. Reverse the digit of a multiple of 25 which is less than 100 to get a multiple of 19.

6. Given a 3 digit number N which is a multiple of 6,7 and 8, what is the least value of N?

Answer 1

possible 2 digit primes are

11, 13,17, 19,

23, 29

31, 37

41,43,47

53,57,59

61,67

71, 73, 79

83, 87, 89

91, 97

but if the cards are just 1,2,3 and 4

that narrows the possible pairs down to

11,13, 23,31,41 and 43

if the cards have different numbers that means only

23 and 41

their difference is |41-23|= 18

least and greatest even numbers between 100 and 200 are

102 and 198

difference = 198-102 = 96

UNLESS you meant to incude 100 and 200 then

difference = 100

factors of 72 include

1,72

2,36

3,24

4,18

6,12

8,9

only 4 and 18 sum to 22

factors of 48 are

1,48

2,24 quotient = 24/2 = 12

3,16

4,12

6,8

multiples of 25 less than 100 are

25, 50,75

reverse the digits gives 52,05 or 57

multiples of 19 include

19,38,57, 76, 95, ...

number you want is 75

reversed it's 57 = 3x19

3 digit multiples of 6,7&8 include

6x7x16=672

6x7x8= 336

6x7x4=168

least value of N = 168