I am currently preparing to take an entrance exam for a university in my country.I have tried to do an exercise but no matter how hard I try it does not give me the result. Is the next:
At the concert, they sell twice as many standing places as seats. A quarter of the standing places and half of the seats are sold out of the total capacity. What is the total number of places in the concert hall if there are currently 1,000 unsold places?
The correct answer is 1500 places, but the answer Iget is always higher I got 1750, 2500, 3000 and 5000
If the number of seats is $a$ as there are twice as many standing places as seats there are $2a$ standing places so total is $3a$. Sold standing places-$\frac{2a}{4}$ Sold seats-$\frac{a}{2}$. SO $3a-a=1000$ , therefore $3a$ is $1500$ which means there are $1500$ places in total