Hi ,
Could'nt sort this one out.
For all integers x and y, the operation 'd' is defined by x 'd' y = (x+2)^2 + (y+3)^2. What is the value of integer t?
(1) t 'd' 2 = 74
(2) 2 'd' t = 80
My answer B. OA is C.
Thanks
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x 'd' y = (x+2)^2 + (y+3)^2krishna kumar wrote:Hi ,
Could'nt sort this one out.
For all integers x and y, the operation 'd' is defined by x 'd' y = (x+2)^2 + (y+3)^2. What is the value of integer t?
(1) t 'd' 2 = 74
(2) 2 'd' t = 80
My answer B. OA is C.
Thanks
from statement 1
t 'd' 2=(t+2)^2 + (2+3)^2 =74
(t+2)^2+25=74
(t+2)^2=49 (t+2)^2=7,-7 so you will get 2 values for t i.e 5,-9
From statement 2
2 'd' t = (2+2)^2 + (t+3)^2.=80
16+(t+3)^2=80
(t+3)^2=64
(t+3)=8,-8 so t=5 and t=-11
comibining 1 and 2 you can be sure value of t as 5
Ideation without execution is delusion
For all integers x and y, the operation 'd' is defined by x 'd' y = (x+2)^2 + (y+3)^2. What is the value of integer t?
(1) t 'd' 2 = 74
(2) 2 'd' t = 80
1) (t+2)^2 + (2+3)^2 = 74
this is quadratic expression hence we get 2 values for t, so 1 alone is insuffcient
2) (2+2)^2 + (t+3)^2 = 80
this is quadratic expression hence we get 2 values for t, so 2 alone is insuffcient
On sloving we get 1 common answer 5
Hence is C is the option
(1) t 'd' 2 = 74
(2) 2 'd' t = 80
1) (t+2)^2 + (2+3)^2 = 74
this is quadratic expression hence we get 2 values for t, so 1 alone is insuffcient
2) (2+2)^2 + (t+3)^2 = 80
this is quadratic expression hence we get 2 values for t, so 2 alone is insuffcient
On sloving we get 1 common answer 5
Hence is C is the option