How to Solve It?

Solve. A clock loses 2 minutes every 8 hours. Avirupa’s mom plans to set the alarm at 11 p.m. on Sunday night to get Avirupa up each morning. Avirupa has to get up each day no later than 7 a.m. What time should her mom set the alarm to be sure that Avirupa isn’t late to school any day, Monday through Friday?

See here. There are13 eight-hour intervals between 11 p.m., Sunday and 7 a.m.,   Friday.

Total loss = 13 × 2 = 26 minutes.

7:00 a.m. − 0:26 minutes = 6:34 a.m.

The alarm needs to be set for 6:34 a.m. to be sure that Avirupa gets up by 7 a.m. on Friday.


  1. 1 3 5 horizontal
    2 3 4 vertically. And vice versa

    3 is common and sum is rest two is same both ways.

  2. If x1,x2,x3,x4 &x5 are 5 numbers ;
    If Any xi comes in center i=1,2,3,4,5;
    Then sum of two is sum of remaining two excluding xi;
    If xi=1 remainings are 2,3,4 &5 :- 2+1+5( let it be Horizontal)=3+1+4(let it be vertical);
    3+1+4 ( let it be Horizontal)=2+1+5(let it be vertical);

    If xi=2 remainings are 1,3,4 & 5:- Solution not possible;
    If xi=3 remainings are 1,2,4 &5 :- 1+3+5(H)=2+3+4(V);
    If xi=4 remainings are 1,2,3 & 5:- Solution not possible;
    If xi=5 remainings are 1,2,3,4 – (1+5+4)(H)=(2+5+3)(V);

  3. There are two possibilities in adding the five numbers to equal eight: 1,2,5 and 1,3,4. The number common to both permutations is 1. Therefore, the number in middle can only be 1.

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