A bill for ₹ 70 is paid by means of ₹ 10 notes and ₹ 20 notes. Five notes are used in all. If m is the number of ₹ 10 notes and n is the number of ₹ 20 notes, then _______.
Am + n = 5, 2m + n = 8
Bm - n = 5, m + 2n = 7
Cm + n = 5, m + 2n = 7
Dm - n = 5, m + 2n = 8
Both options A and C are correct.Because, m=3 and n=2, as amount was paid in 5 notes. This is the only correct answer.so, m n=5 ------ (1)m 2n= 3 2x2=3 4=7 --------(2)Therefore, option (c) - m n=5, m 2n=7 is correct.BUT,2m n=2x3 2=6 2---------(3)So, Option (A)- m n=5, 2m n=8 is also correctThis option has two correct answers, please correct this