here got C
i want to think that it is m^2-n^2
(1) insuff as no info about n, but m=10k+3
(2) insuff as no info about m, n=10a+3
together
(10k+3)^2-(10a+3)^2=100k^2+2*3*10k+9-100a^2-10a*2*3-9, we can cancel 9 all other members are divisible by 10 and remaider is 0
remonder
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Source: Beat The GMAT — Data Sufficiency |
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m^2-n^2=(m+n)(m-n)
st(1) m=10a+3 where a is integer Not Sufficient
st(2) n=10b+3 where b is integer Not Sufficient
Combined st(1&2): (10a+3+10b+3)(10a+3-10b-3)/10= (10a+10b+6)(10a-10b)/10
10(a-b)(10a+10b-6)/10 = (10a+10b-6) quotient + 0 remainder
answer C
st(1) m=10a+3 where a is integer Not Sufficient
st(2) n=10b+3 where b is integer Not Sufficient
Combined st(1&2): (10a+3+10b+3)(10a+3-10b-3)/10= (10a+10b+6)(10a-10b)/10
10(a-b)(10a+10b-6)/10 = (10a+10b-6) quotient + 0 remainder
answer C
maihuna wrote:If m and n are positive integers, what is the remainder when
m2 - n2 is divided by 10?
(1) The remainder when m is divided by 10 is 3.
(2) The remainder when n is divided by 10 is 3.
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