Answer:
The cost of each exercise book is 25 sh.
The cost of each pen is 8 sh.
Step-by-step explanation:
Write down the system of equations and then solve.

Best Regards!
Answer:
138 and 210?
Step-by-step explanation:
Do what? Using 5th grade strategies??
You eliminate two equations first then you find one variable, once u figured out one variable plug it into any equation and try to cancel out another variable, youll have two variables in the end and then just plug and u have ur answers