Question

There are two numbers. The sum of 9 times the first number and 4 times the second is 790. The sum of 4 times the first number and 9 times the second number is 640. Find the smaller number.

Answer 1

Second number is smallest which is 4

Answer 2

let one no. be x and the other one be y
first case: 9x+4y=790                                 .........1
∴9x=790-4y
∴  x=(760-4y)/9                             ........2
second case: 4x+9y=640  
by substituting the value of x we get
[4×(790-4y)/9]+9y=640
∴{3160-16y/9]+9y=640
∴3160-16y+81y/9=640
∴3160+65y=5760
∴65y=5760-3160=2600
∴y=2600/65
∴y=40
by subtituting the value of y in equation 2
x= (790-4×40)/9=(790-160)/9=630/9
∴x=70
∴y is the smaller no.