A store sells jars of peanut butter that cost p dollars and jars of jelly that cost j dollars. Winston purchased 3 jars of peanut butter and 2 jars of jelly for $11.50. Peter purchased 2 jars of peanut butter and 4 jars of jelly for $13.00. How much does 1 jar of peanut butter cost? A. $2.00 B. $2.50 C. $3.00 D. $3.50

Answer:The cost of 1 jar of peanut butter is $2.50 ⇒ answer BStep-by-step explanation:* Lets change the story problem to equations to solve it- The cost of a jar of peanut butter is p dollars- The cost of a jar of jelly is j dollars- Winston purchased 3 jars of peanut butter and 2 jars of jelly for $11.50- Peter purchased 2 jars of peanut butter and 4 jars of jelly for $13.00* Lets write the equations∵ The cost of a jar of peanut butter is p dollars and the cost of a jar    of jelly is j dollars∵ Winston purchased 3 jars of peanut butter and 2 jars of jelly for $11.50∴ 3p + 2j = 11.50 ⇒ (1)∵ Peter purchased 2 jars of peanut butter and 4 jars of jelly for $13.00∴ 2p + 4j = 13.00 ⇒ (2)- Lets solve this system of equation by using elimination method- Multiply equation (1) by -2∴ -6p - 4j = - 23 ⇒ (3)- Add equations (2) and (3)∴ -4p = -10 ⇒ divide both sides by -4∴ p = 2.5∵ p is the cost of 1 jar of peanut butter* The cost of 1 jar of peanut butter is $2.50