The sum of 2 nos is 4000 . If 15 % of one is equal to 25% of the other no. Find the nos ?

2 Answers
Dec 2, 2016

Answer:

The numbers are #x=2500# and #y=1500#.

Explanation:

Let x and y be the two numbers.

First equation:
#x+y=4000#

Second equation (remember #15%# of a number means #.15# times the number):
#.15x=.25y#

Isolate y in the first equation:
#x+y=4000#
#y=4000-x#

Substitute this into the second equation:
#.15x=.25(4000-x)#
Distribute and solve for x:
#.15x=1000-.25x#
#.4x=1000#
#x=2500#

Substitute this into first equation written in terms of y:
#y=4000-x#
#y=4000-(2500)#
#y=1500#

Dec 3, 2016

Answer:

#a=2500" "b=1500#

Explanation:

Let one value be represented as #a#
Let the other letter be represented as #b#

Then we have #a+b=4000#...Equation(1)

Also we have:

#15/100a=25/100b#

#=>a=25/(cancel(100))xx(cancel(100))/15 b#

#a= 5/3b# ......................................Equation(2)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#color(blue)("Determine the value of "b)#

substitute for #a# in equation(1) using equation(2)

#a+b=4000" "->" "5/3b+b=4000#

#8/3b=4000#

#b=3/8xx4000#

#color(blue)(b=1500)#

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#color(blue)("Determine the value of "a)#

#color(blue)(a=4000-1500 = 2500)#

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#color(brown)("Check")#

#15/100a" "=25/100b#

Consider the LHS
#15/100xx2500 = 375#

Consider the RHS
#25/100xx1500=375#

#LHS=RHS" "# so correct