Answer: She has 21 lira coins.
Step-by-step explanation:
Given, Laura collects old foreign coins. She has 83 coins in total. She has 53 lira and drachma coins. She has 51 lira and peseta coins.
Let x = the number of lira coins.
y= the number of drachma coins.
z= the number of peseta coins.
Then, as per given, we have
x+y+z=83 (i)
x+y=53 (ii)
x+z=51 (iii)
From (ii) and (iii)
y=53-x
z=51-x
Put these values in (i) , we get
x+(53-x)+(51-x)=83
⇒ x+53-x+51-x=83
⇒ 104-x=83
⇒104-83=x
⇒x= 21
Hence, she has 21 lira coins.
