Is x=y one solution or infinite

Ihave a 69 and an 82. the 69 is worth 40% of my grade and the 82 is worth 15%. can someone tell me my current average grade.

Aplane flies around trip to philadelphia it flies to philadelphia at 220 miles per hour and back home with a tailwind at 280 miles per hour if the total trip takes 6.5 hours how many miles does the plane fly round trip

Aprojectile is thrown upward so that its distance above the ground after t seconds is given by the function h(t) = -16t2 + 704t. after how many seconds does the projectile take to reach its maximum height?