Rithvik's Blog 11+

A number is put into a machine. First, the machine adds 7. Then it doubles the result. Finally, it subtracts 9. The final answer is 25. What was the original number?

A row of squares is made from matchsticks. 1 square uses 4 matchsticks 2 squares in a row use 7 matchsticks 3 squares in a row use 10 matchsticks How many matchsticks will 20 squares in a row use?