A rectangle length is one less than triple the width if the perimeter is 94 inches determine the dimensions of the rectangle

Pls! does anybody know a shortcut for answering these types of questions in the future?

Fatima plans to spend at least $15 and at most $20 dollars on sketch pads and pencils. if she buys 2 sketchpads, how many pemcils can she buy while staying in her price range? fatima can buy between and pencils. ? (type whole numbers. use ascending? order.)

Me d is also an option but i couldn't get it in the picture