The number of mandarin oranges Valen bought in March was 40% more than in February. In April, he bought 70% less mandarin oranges than in March. If there were 348 less mandarin oranges in April than February, how many mandarin oranges did Valen buy in March?

February	March	April
5x10	7x10
	10x7	3x7
50 u	70 u	21 u

100% + 40 = 140%
140% = ¹⁴⁰₁₀₀ = ⁷₅
March : February = 7 : 5 

100% - 70% = 30%
30% = ³⁰₁₀₀ = ³₁₀
April : March = 3 : 10

The number of mandarin oranges in March is repeated.  Make the number of mandarin oranges in March is the same.  LCM of 7 and 10 is 70.

Number of less mandarin oranges in April than February
= 50 u - 21 u
= 29 u

29 u = 348

1 u = 348 ÷ 29 = 12

Number of mandarin oranges that Valen bought in March
= 70 u
= 70 x 12
= 840

Answer(s): 840