In a two-digit number, the tens' digit is 1 less than the units' digit. If the digits are interchanged, the sum of the number obtained and the original number is 143. Find
the number.

67

Step-by-step explanation:

Number: AB

A = B-1

BA + AB = 143

10*B + A + 10*A + B = 143

11A + 11B = 143

A + B = 13

(B-1) + B = 13

2B = 14

B = 7

A = 6

The number is 67

check: 6 = 7-1   and   67 + 76 = 143

  or  

step-by-step explanation:

if the four friends split the cost, p, of the pizza evenly, then each friend pays one-fourth of the cost of the pizza.

the expression is   or