Math Word Problems Demystified - A Self Teaching Guide

22 x
 11 x
 1 ¼ 11 x
 11 xþ 10

11 x
 1 ¼ 10

11 x
 1 þ 1 ¼ 10 þ 1

11 x¼ 11

111 x

111

¼

11

11

x¼1 (ten’s digit)

xþ 1 ¼ 1 þ 1 ¼2 (one’s digit)

The number is 12.

5. Letx¼the ten’s digit and 11
   x¼the one’s digit; then the original
   number is 10xþ(11
   x); the reversed digits number is 10(11
   x)þx

2 ð 10 xþ 11 
xÞþ 7 ¼ 10 ð 11 
xÞþx

2 ð 9 xþ 11 Þþ 7 ¼ 110 
 10 xþx

18 xþ 22 þ 7 ¼ 110 
 10 xþx

18 xþ 29 ¼ 110 
 9 x

18 xþ 9 xþ 29 ¼ 110 
 9 xþ 9 x

27 xþ 29 ¼ 110

27 xþ 29 
 29 ¼ 110 
 29

27 x¼ 81

271 x

271

¼

81

27

x¼3 (ten’s digit)

11 
x¼ 11 
 3 ¼8 (one’s digit)

The number is 38.

104 LESSON 10 Solving Digit Problems