hello.need help on the 2 questions

tickets for a concert are available at two prices. the more expensive ticket is $30 more than the cheaper one. Find the cost of each type of ticket if a group can buy 10 more of the cheaper tickets than the expensive ones for $1800

the more expensive ticket is 30 + x

less expensive ticket is x

10 more of the cheaper tickets than the expensive ones for $1800

10 + x ... ?

the members of a club hire a bus for $2100, seven members withdraw from the club and the remaining member have to pay $10 more each to cover the cost. How many members originally agreed to go on the bus.

let x be number of people

so x= 2100,

x-7= ... ?

thank you guys