Using-only-the-integers-4-to-8-how-many-even-numbers-can-be-formed-if-each-must-lie-between-4000-and-9000-

Question Number 27513 by NECx last updated on 08/Jan/18

U s i n g o n l y t h e i n t e g e r s 4 t o 8,

h o w m a n y e v e n n u m b e r s c a n b e

f o r m e d i f e a c h m u s t l i e b e t w e e n

4000 a n d 9000 ?

Answered by Rasheed.Sindhi last updated on 08/Jan/18

A s t h e n u m b e r s a r e b e t w e e n

4000 & 9000, s o t h e n u m b e r o f

p o s i t i o n s i s 4 .

E a c h o f 1000 t h, 100 t h & 10 t h

p o s i t i o n s c a n b e f i l l e d w i t h

4, 5, 6, 7 & 8 i - e i n 5 w a y s b u t

t h e u n i t p o s i t i o n c a n b e f i l l e d

w i t h 4, 6 & 8 i - e i n 3 w a y s b e c a u s e

t h e n u m b e r s a r e e v e n .

∴ T o t a l w a y s = 5.5.5.3 = 375