alleryଦୁଇଟି କଲମ ଏବଂ ଗୋଟିଏ ପେନସିଲ୍ର ମୂଲ୍ୟ Rs 25; ଗୋଟିଏ କଲମ ଏବଂ ଦୁଇଟି ପେନସିଲ୍ର ମୂଲ୍ୟ Rs 20। ଗୋଟିଏ କଲମର ମୂଲ୍ୟ କେତେ?
ARs 12
BRs 10
CRs 5
DRs 15
Answer & Solution
Correct answer: B. Rs 10
ମନେକରନ୍ତୁ ଗୋଟିଏ କଲମର ମୂଲ୍ୟ $p$ ଏବଂ ଗୋଟିଏ ପେନସିଲ୍ର ମୂଲ୍ୟ $q$। ତେବେ $2p+q=25$ ଏବଂ $p+2q=20$। ପ୍ରଥମ ସମୀକରଣକୁ ଦୁଇଗୁଣ କରି ସେଥିରୁ ଦ୍ୱିତୀୟଟି ବିୟୋଗ କରନ୍ତୁ: $(4p+2q)-(p+2q)=50-20$, ଯାହାଦ୍ୱାରା $3p=30$ ଏବଂ $p=10$ ମିଳେ। ଗୋଟିଏ କଲମର ମୂଲ୍ୟ Rs 10 (ବିକଳ୍ପ B)।
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