Question

A person has 20 coins, all nickels and dimes, worth one dollar and 40 cents. How many nickels are there?

If n = number of nickels and d = number of dimes, which system of equations represents the problem?

Answer 1

The answer is

n + d= 20 and 5n + 10d= 140

Explanation:

Answer 2

is there one that looks like
\[n+d=20\\
5n+10d=140\]