Lindsay is 5 years younger than Mark. Seven years ago, the sum of their ages was 31 .Let l be Lindsay's age and let m be Mark's age.Which system of equations represents this situation?Choose 1 answer:(A) {l=m+5(l−7)+(m−7)=3(B) {l−7=(m−7)−5l+m=31(C) {l=m−5(l−7)+(m−7)=3(D) {l−7=(m−7)+5l+m=31
Q. Lindsay is 5 years younger than Mark. Seven years ago, the sum of their ages was 31 .Let l be Lindsay's age and let m be Mark's age.Which system of equations represents this situation?Choose 1 answer:(A) {l=m+5(l−7)+(m−7)=3(B) {l−7=(m−7)−5l+m=31(C) {l=m−5(l−7)+(m−7)=3(D) {l−7=(m−7)+5l+m=31
Define Variables: Let's define the variables based on the information given:Let l be Lindsay's current age.Let m be Mark's current age.We are told Lindsay is 5 years younger than Mark, which gives us the equation:l=m−5
Represent Ages Seven Years Ago: Next, we need to represent the information about their ages seven years ago. Seven years ago, Lindsay's age would be l−7 and Mark's age would be m−7. The sum of their ages at that time was 31, so we have the equation:(l−7)+(m−7)=31
Simplify Equation: Now, let's simplify the second equation:l−7+m−7=31l+m−14=31l+m=31+14l+m=45
Form System of Equations: We have two equations now:1. l=m−52. l+m=45This system of equations represents the situation given in the problem. Let's match this system with the answer choices.
Match with Answer Choices: Comparing our system of equations with the answer choices, we find that:Choice (C) {l=m−5,(l−7)+(m−7)=31} matches our system of equations.
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