Measurement of the relative branching fractions of <math><msup><mi>B</mi><mo>+</mo></msup><mo>→</mo><msup><mi>h</mi><mo>+</mo></msup><msup><mi>h</mi><mrow><mo>′</mo><mo>+</mo></mrow></msup><msup><mi>h</mi><mrow><mo>′</mo><mo>−</mo></mrow></msup></math> decays

The relative branching fractions of B+→h+h′+h′− decays, where h(′) is a pion or kaon, are measured. The analysis is performed with a data sample, collected with the LHCb detector, corresponding to an integrated luminosity of 3.0 fb−1 of pp collisions. The results obtained improve significantly on previous measurements of these quantities, and are important for the interpretation of Dalitz plot analyses of three-body charmless hadronic decays of B+ mesons.