Question

Robin breaks his piggy bank and counts to see a total of 23 coins adding to $2.75\$$. Of the total coins, m coins are worth $\$0.25$ each and n coins are worth $\$0.05$ each. If he did not put any other type of coin in the piggy bank, then which of the following pairs of equation, best describes the given situation?

• A. m + n = 23 ; mn = 2.75
• B. m + n = 23; 0.25n + 0.05m = 2.75
• C. 0.25m + 0.05n = 23 ; m + n = 2.75
• D. m + n = 23; 0.25m + 0.05n = 2.75

Answer 1

The correct option is D m + n = 23; 0.25m + 0.05n = 2.75

Step 1: Underline the key words
Robin breaks his piggy bank and counts to see a total of 23 coins adding to $2.75\$$ . Of the total coins, m coins are worth $\$0.25$ each and n coins are worth $\$0.05$ each. If he did not put any other type of coin in the piggy bank, then which of the following pairs of equation, best describes the given situation?

Step 2: Recognize the variable : m and n
Decipher the relation b/w the variables :
A total of 23 coins ; m + n = 23
m coins are worth $\$0.25$ each and n coins are worth $\$0.05$ each then total value = 0.25m + 0.05n = 2.75

Hence the answer is C