Question

1. Peter, John and Ronny working together take 30 minutes to slash a piece of land. peter and Ronny together take 40 minutes while peter and John together take 45 minutes. How long would each one of them take to slash the same piece of land 
2. Two types of sugar P and Q are such that P costs sh. 50 per kg and Q costs sh.60 per kg. In what proportion must P and Q be mixed so that by selling the mixture at shs 64.80 a profit 20% is realized.  

Answer 1

1. P+J+R =¹/₃₀
   P+R = ¹/₄₀
   P+J =¹/₄₅
   ¹/₄₅ + R =¹/₃₀
   R = ¹/₃₀ − ¹/₄₅
   R=¹/₉₀ Rony = 90mins
   J= ¹/₃₀ − ¹/₄₀ = ¹/₁₂₀  John=120mins
   P= ¹/₄₀ − ¹/₉₀ = ¹/₇₂  peter=72mins
2. let be n:1
   (50n +60)  120 =64.80
   (  n + 1  )   100
   (50n + 60)1.2 =64.8n + 64.8
   60n + 72 =64.8n +64.8
   4.8n = 7.2
   n=³/₂ 
   ³/₂ : 1
   =3:2