Westonci.ca is the best place to get answers to your questions, provided by a community of experienced and knowledgeable experts. Our platform connects you with professionals ready to provide precise answers to all your questions in various areas of expertise. Discover detailed answers to your questions from a wide network of experts on our comprehensive Q&A platform.

a) six pens and five pencils cost $2.50 while three pens and two pencils cost $1.15 . what will be the cost of a pen and 4 pencils . please help me

Sagot :

Let pen's cost be x and pencil's cost be y.

6x + 5y = 2.50
3x + 2y = 1.15

Thus, 3x = 1.15 - 2y
Therefore, 6x = 2.30 - 4y

Substituting the value of 6x ;

(2.30 - 4y) + 5y = 2.50

or, 2.30 + y = 2.50

=> y = 0.20.

Substituting the value of y ;

6x = 2.30 - 4(0.20)
6x = 2.30 - 0.80 = 1.5
6x = 1.5
=> x = 0.25

Thus, 1 pen costs 0.25 $ and 1 pencil costs 0.20$.

Thus, cost of one pen is 0.25$.
Cost of 4 pencils is 0.80 $

0.25$ + 0.80$ = 1.05$
x - pen
y - pencil

[tex]6x+5y=2.5\\ 3x+2y=1.15\\\\ 6x+5y=2.5\\ -6x-4y=-2.3\\ --------\\ y=\$0.2\\\\ 6x+5\cdot0.2=2.5\\ 6x+1=2.5\\ 6x=1.5\\ x=\$0.25\\ \\x+4y=0.25+4\cdot0.2=\boxed{\$1.05 }[/tex]