Learn Quantitative Aptitude with Free Lessons & Tips

sure, you can improve your aptitude/maths solving ability. First you should be well in all concepts then you should practise repeatedly, if you take 60 sec now for a question it may come to 10-15 seconds only by practicing the topic again and again.My suggestion is to take any question bank and start practicing.

Start with basics and fundamental concept which you will get in 6,7,8,9 class maths text book. If u r running short of time than go through the concept provided in solved example of RS AGGRAWAL solve all exercise question of  RS AGGRAWAL without seeing the answer and cross-check it. Try to create ur own shortcut method for each topic and make a note of it. Last but not least practise as many question as possible along with mock test  to grab ur hand completely on quant.

Let's say the no is X

X÷15= Y+14

X÷16= Z+15

If Y=X+1

And Z= X+1

We will get the no which is directly divisible by 15 and 16.

So we calculate the Lowest common multiple of 15 and 16. We get 240.

Now we need to subtract 1 from it to get the exact no.

Therefore the answer is 239