On sixth of February, Sudhir tells his aunt , “I went for a picnic with my classmates exactly 15 days ago.” When was his picnic?

a) 22nd January b) 28th February c) 21stJanuary d) 21stFebruary

22nd January, since there are 31 days in January

therefore till Feb 1st .. we subtract 6 days and then from 31st we subtract 9 days.. in total subtracting 15 days

system of linear equation

step-by-step explanation:

as given in the data

a= 20 , b= -12

let us suppose that it is a straight line equation

now we know the formula for the system of linear equation

b= ma + c )

here m is slope of a straight line which is equal to formula

m=   (ii)

and here c is a constant

now putting the value of a and b in equation (ii)

m=

m=

putting the value of a,b and m in equation (i) gives us

-12 = + c

-12=-12 + c

adding 12 to both sides

-12 +12 = -12 +12 +c

0 =c

or c=0

as the value of the constant is zero which gives us that it is a linear equation and this order pair satisfies the system of linear equations.