Question

Kiran has 27 nickels and quarters in his pocket, worth a total of $2.75.

Answer 1

Answer:

$\begin{cases}n+d = 27\\0.05n+0.10d = 2.75\\\end{cases}$

====================================================

Explanation:

n = number of nickels

d = number of dimes

The n and d are placeholders for positive whole numbers.

Since we have 27 coins, we know that n+d = 27. The two subcounts must add to the grand total of 27. That explains how the first equation is set up.

The second equation is set up by looking at the dollar amount each group of coin brings in.

0.05n = amount of money in dollars the nickels bring in

0.10d =  amount of money in dollars the dimes bring in

0.05n+0.10d = total amount of money in dollars = 2.75

The single curly brace to the left of the equations tells the reader we're dealing with a system of equations. The equations are tied together.