Darla got a job at a jewelry store. She gets paid $20 for each ring she sells and $50 for each necklace she sells. How much will she earn if she sells 15 rings and 9 necklaces?

Hello i need some with trigonometric substitutions. [tex]\int\limits^a_b {x} \, dx[/tex]

What is the value of x in the equation 2(x-4) = 4(2x + 1)?

Water flows at a steady rate from a tap. its takes 40 seconds to fill a 4 litre watering can from the tap. the rate at which water flows from the tap is halved. complete: 4 litres into cm3