Question

Three pens each having cost Rs5, 30 and 100/- and we want to buy 100 pcs in Rs1000/- .So, what is the numbers of each pens.

Answer 1

Answer:

₹5 pen= 94, ₹30 pen= 1, ₹100 pen= 5

Step-by-step explanation:

₹5 pen= x, ₹30 pen= y, ₹100 pen= z

• (1) x+y+z=100

• (2) 5x+30y+100z=1000

(2) - (1)*5:

• 5x+30y+100z -5(x+y+z)=1000-500
• 25y+95z=500
• 5y+19z=100
• 19z=100-5y
• 19z=5(20-y)
• z=5 is the only integer solution,
• then y=1
• then x=100-(y+z)=94

So number of pens are :

₹5 pen= 94, ₹30 pen= 1, ₹100 pen= 5

Proof:

₹5*94+₹30*1+₹100*5=₹1000

₹1000=₹1000