Ravi purchases 90 pens and sells 40 pens at a gain of 10% and 50 pens at a gain of 20%. Had he sold all of them at a uniform profit of 15% he would have got Rs. 40 less. Find the cost price of each pen.

Sarita sells a Phone at a profit of 20%. If she had bought it at 20% less and sold it for Rs. 180 less, she would have gained 25%. Find the cost price of the Phone.

Find the least number which when divided by 12, 15, 18 and 27 leaves remainders 10, 13, 16 and 25 respectively.

The mean of 12 observations is 15. One more observation is included and the new mean becomes 16. The 13th observation is

If two complimentary angles are in the ratio of 4:5, find the greater angle.

Mohan invested Rs. 100,000 in a garment business. After few months, Sohan joined him with Rs. 40000. At the end of the year, the total profit was divided between them in ratio 3:1. After how many months did Sohan join the business?

3 years ago, the ratio of Maya’s and Shikha’s age was 5:9 respectively. After 5 years, this ratio would become 3:5. Find present age of Maya?

Three numbers are in the ratio of 3:5:10 and their LCM is 630. Find their HCF.