The cost of an apple is twice that of a banana and the cost of a banana is 25% less than that of a guava. If the cost of each type of fruit increases by 10%, then the percentage increase in the cost of 4 bananas, 2 apples and 3 guavas is

let the cost of a banana be Rs b 

and hence cost of an apple = 2b

and guava cost be = 4/3 b 

now cost of every fruit is increased by 10% 

and hence 

 cost of a banana be Rs 1.1b

and hence cost of an apple = 2.2 b

and guava cost be = (4.4/3)b 

initially , 4 bananas + 2 apples + 3 guavas = 13/3 b 

finally , 4 bananas + 2 apples + 3 guavas = 14.3/3 b 

and hence percentage increment = $$\frac{(14.3-13)}{13}$$ x 100 = 10 %