Question

The area of a parallelogram with adjacent sides determined by the vectors a and b is 30. The area of the parallelogram with adjacent sides determined by the vectors (a + b) and a is 

(a) 100 

(b) 30 

(c) 24 

(d) 60

Answer 1

Answer is (b) 30

Explanation:

Given |a × b| = 30

Now, |a × (a + b)|

= |a × a + a + b|

= |0 + a × b|

= |a × b|

= 30